Squeeze form uploads: CF7 (free), Gravity Forms single-/multi-file (Premium).
Safer huge uploads (soft megapixel, thumb skip, client-compressed markers).
Bulk savings totals + completion review ask.
Menu: Media → Squeeze Bulk Tools; DE/ES/FR translations.
1. Introduction
Welcome to the Squeeze Plugin Documentation
Squeeze is a powerful WordPress plugin that optimizes images directly in your browser, improving website speed without relying on external servers. This documentation covers everything from installation to advanced settings for both free and premium users.
Key Benefits:
Compress images directly in your browser.
No limits on the number of images compressed.
WEBP conversion for modern browser support.
No third-party servers involved, ensuring privacy.
Front-end form uploads: Contact Form 7 (free); Gravity Forms (Premium).
The link above is also available in the Free version, when you navigate to Settings → Squeeze → Upgrade tab:
Select desired billing plan (annual or lifetime) and complete the checkout process.
After payment, you will receive a confirmation email with the download link and license key.
Save the Premium’s version ZIP file (squeeze-premium-latest.zip) to your computer. You can do that by clicking on the download link in the email (Download the plugin’s Premium version).
Install the Premium version by navigating to Plugins → Add New Plugin → Upload Plugin.
Upload the ZIP file and click Install Now.
Activate the Premium version of the plugin after installation.
After activation, copy and paste the license key from the email. You can do that on the Settings page of the plugin (Settings → Squeeze):
2.3 Initial Setup
Navigate to WordPress Dashboard → Settings → Squeeze.
Adjust the compression settings as you need.
Alternatively, you can access the Squeeze Settings page from the plugins list:
3. Basic Settings
Here you can set up basic settings of the Squeeze Plugin.
3.1 Squeeze on Upload
Enabling this option compresses images on upload. Supported flows:
Media Library / classic upload
Gutenberg Image block and GenerateBlocks media blocks (pre-upload, in the browser)
Instant Images stock-photo imports — squeezed right after the image lands in the Media Library (Media Library page, media modal, and editor sidebar)
Voxel theme create-post and file/gallery fields (free)
Elementor editor uploads (Premium only)
Squeezing the image right on upload in Gutenberg Editor
If the compressed file would be larger than the original, Squeeze can skip replacing it.
WordPress 7.1 note: while Squeeze on upload is enabled, Squeeze turns off WordPress’s own client-side media processing, so Gutenberg uploads keep your Squeeze quality settings, Direct WebP, backups, and thumbnail rules. If you would rather use core’s browser pipeline (HEIC “just works”, HDR gain-map thumbnails), turn Squeeze on upload off — bulk and manual squeeze still work. HEIC/HEIF files are not squeezed either way.
This setting covers Media Library / editor / theme upload pipelines (Gutenberg, GenerateBlocks, Instant Images, Voxel; Elementor in Premium). It does not control front-end form file fields — use Squeeze form uploads below for Contact Form 7 and Gravity Forms.
3.2 Squeeze form uploads
Enable under Settings → Squeeze → Basic Settings → Squeeze form uploads (on by default on fresh installs).
When enabled, Squeeze compresses images in the visitor’s browser when they pick files on supported front-end forms — before the file is uploaded or the form is submitted. Uses your format / quality settings. Non-images and failed compressions are left alone (fail-open). While optimization is running, submit is delayed and the field may show “Compressing the image…”.
Included today:
Contact Form 7 — free. Native file inputs.
Gravity Forms — Premium only. Single-file and multi-file (Plupload) fields (fileupload / post_image). Scripts load only when the rendered form has a file field.
Not the same as Squeeze on upload: separate checkbox.
Not supported yet: WPForms (and other form plugins beyond CF7 / GF).
3.3 Backup Original Image
If enabled, Squeeze will create a backup of the original image before applying compression.
The backup can be restored if needed, thus you can re-compress your image with different compression options.
The backup is saved next to the file as photo.bak.jpg / photo.bak.png.
With Direct WebP enabled, the backup is WebP too — e.g. photo.bak.webp.
Backups also apply to Directory Squeeze now (see 9.1), not only the Media Library.
3.4 Delete plugin data on uninstall
When enabled, uninstalling Squeeze removes its settings, stats, and compression status metadata.
Image files are never deleted.
3.5 Image Formats
Choose which image formats (JPEG/JPG, PNG, AVIF, WEBP) should be optimized.
3.6 WebP delivery
Choose one strategy under Settings → Squeeze → Basic Settings → WebP delivery.
1. Direct WebP (Recommended) Replace originals with .webp on disk. Lowest storage; URLs change to .webp. If you deactivate Squeeze while this mode was used, some hard-coded .jpg/.png links may break — reselect images in posts/pages or restore from backup.
2. Rewrite <img> src to WebP URLs in HTML (Advanced) Keeps JPEG/PNG in uploads; WebP copies live under /wp-content/squeeze-webp/. Squeeze rewrites src/srcset in page HTML to the WebP path. Best when .htaccess rewrites are unavailable (Nginx, CDN, etc.). Database URLs are not changed.
3. Keep JPEG/PNG URLs — server serves WebP (Advanced, Apache / .htaccess) Keeps originals; WebP files go to squeeze-webp. HTML still shows .jpg/.png. Server rewrite rules serve WebP bytes when the browser supports it.
Switching modes does not migrate existing files automatically — re-squeeze after changing mode. Leftover JPEG/PNG + WebP pairs or files under squeeze-webp may remain until cleaned up.
On a fresh install, or if neither delivery option was ever saved, Squeeze behaves as Direct WebP. The settings screen, the Media Library, and bulk/directory runs all agree on that default.
If you also run WebP Express, Squeeze only warns about the conflict when Direct WebP is not active — Direct WebP does not use the rewrite/replace path that conflicts with it.
3.7 Squeeze Thumbnails
Select which thumbnail sizes should be compressed along with the original image.
3.8 Squeeze Timeout
Set a time limit (in seconds) for squeezing an image (along with all the thumbnail sizes you selected above).
If you experience errors, try increasing this value.
3.9 Excluded images
Enter a list of images to skip during bulk or upload squeeze.
Full URLs or partial strings (filename substrings) are allowed — one per line.
Excluded images are omitted from Bulk Squeeze and from the Media Library “Non-Squeezed” filter.
4. Premium Features
Premium adds Media Library comparison, original resize, Bulk Squeeze from a Page, Elementor on-upload squeeze, CDN URL mapping, and Gravity Forms form uploads — still entirely in the browser, with no external servers.
4.1 CDN URL
If your site serves uploads from a CDN, enter that base URL so Squeeze can map CDN links to local files. Used for all WebP delivery modes and for Bulk Squeeze from a Page. With WP Offload Media, the provider/CDN URL is often auto-detected; you can still set CDN URL manually if needed.
4.2 Max Image Width
Set a maximum width for the original size of images.The thumbnails width (as well as scaled images) will not be affected.
Leave empty to keep the original width.
Resizing happens while the image is decoded in the browser, which keeps memory use lower on very large files.
Thumbnail sizes that would end up larger than the resized original are deleted from disk instead of being left behind.
4.3 Max Image Height
Set a maximum height for the original size of images.The thumbnails height (as well as scaled images) will not be affected.
Leave empty to keep the original height.
Resizing happens while the image is decoded in the browser, which keeps memory use lower on very large files.
Thumbnail sizes that would end up larger than the resized original are deleted from disk instead of being left behind.
4.4 Image comparison
Compare the original and squeezed image side by side in the Media Library before you commit to compression.
Open an image in Media → Library.
Enable the Compare Squeeze toggle.
Drag the slider to compare before/after, and check the estimated file size and savings %.
Optionally tweak quality settings in the preview panel, then run Squeeze when you are satisfied.
The preview runs in your browser and does not replace the file by itself. In the free version the toggle is invisible.
4.5 Elementor integration
Squeeze on upload while editing in Elementor (Premium). Free version covers Gutenberg, GenerateBlocks, and Voxel.
4.6 Gravity Forms uploads
With Squeeze form uploads enabled and Squeeze Premium active, visitor photos on Gravity Forms are compressed in the browser before they hit your server.
Works on single-file and multi-file upload fields.
Uses the same quality / format as other Squeeze compressions.
Free Squeeze still compresses Contact Form 7 file fields when Squeeze form uploads is on; Gravity Forms requires Premium (same gate as Elementor).
5. JPEG Settings
Here you can set up compression options for the JPEG images.
Quality
Adjust the compression quality for JPEG images. A lower value reduces file size but may decrease visual quality.
Smoothing
Apply a smoothing effect to JPEG images to reduce noise and artifacts.
5.1 JPEG Advanced Settings
Here are listed more precise settings for experienced users. The options below are setted up to keep the most optimal result for your image compressions. Please keep them with their default values, if you are not sure what you’re doing 🙂
Pointless Spec Compliance: Toggle compliance with unnecessary JPEG format specifications.
Progressive Rendering: Optimize images for progressive loading.
Optimize Huffman Table: Reduce image file size by optimizing the Huffman coding.
Channels: Control which color channels to keep in JPEG images.
Quantization: Adjust color quantization settings for optimized storage.
Trellis Multipass: Perform multiple passes of trellis optimization to reduce file size.
Optimize Zero Block Runs: Optimize sequences of zero values to enhance compression.
Optimize After Trellis Quantization: Further refine JPEG compression efficiency.
Trellis Quantization Passes: Define the number of passes for trellis quantization.
Auto Subsample Chroma: Automatically adjust chroma subsampling to balance quality and size.
Subsample Chroma By: Manually set the chroma subsampling ratio.
Separate Chroma Quality: Specify a different quality level for chroma components.
Chroma Quality: Control the chroma quality to maintain color accuracy while reducing file size.
6. PNG Settings
Here you can set up compression options for the PNG images.
Quality
Adjust PNG compression quality (0.01–1). Lower values usually mean smaller files; higher values keep more detail.
7. WEBP Settings
Here you can set up compression options for the WEBP images.
Effort
Defines how much processing power should be used to optimize WEBP images.
Quality
Adjust the compression quality for WEBP images.
Lossless
Enable lossless WEBP compression to retain image quality while reducing size.
Near Lossless
Set near-lossless compression for a balance between quality and file size.
8. AVIF Settings
Here you can set up compression options for the AVIF images.
Quality
Adjust the quality setting for AVIF images to optimize performance and file size.
9. Compressing Images
Squeeze allows you to compress images directly from your WordPress Media Library or during the upload process.
Pre-upload compression
With Squeeze on upload enabled, images can be compressed in the browser before they hit the server (Gutenberg, GenerateBlocks, Voxel; Elementor in Premium). Instant Images imports are squeezed right after attach.
With Squeeze form uploads enabled, front-end form file fields are compressed in the visitor’s browser (Contact Form 7 free; Gravity Forms Premium). See Basic Settings → Squeeze form uploads.
Manual Compression
Go to Media → Library (in your WordPress admin dashboard).
Click on an image and find the Squeeze section (in the Grid mode).
Click on the Squeeze button.
In the List mode, you can click on the Squeeze button under the Squeeze column:
Bulk Compression
Navigate to Media → Squeeze Bulk Tools.
You will see progress for how many images are already squeezed, plus Total saved (since version 1.8.0) when savings data exists.
Click Run Bulk Squeeze to compress images that are left.
Click Repeat Bulk Squeeze to re-compress all the images from your Media Library again.
When a run finishes, Squeeze shows how much was saved on that run and may ask for a wordpress.org review (no upsell in that popup).
Bulk Squeeze compresses and uploads one image at a time (sequential) for browser and shared-hosting stability.
Bulk Compression via Media Library
Navigate to Media → Library.
Switch to the List mode:
Select images you want to squeeze. You can also select images that are already being squeezed, if you want to apply new squeezing options to them.
In the Bulk actions dropdown select Squeeze Image and click on the Apply button.
9.1 Directory Squeeze
Navigate to Media → Squeeze Bulk Tools.
Click Select Directory and choose one or more folders to compress all images inside them. Media Library year/month folders (for example /wp-content/uploads/2026/09/) are disabled here — use Bulk Media Library Squeeze for those, so attachment metadata and thumbnail sizes stay in sync.
Click on the Run Directory Squeeze button to start compressing images from the selected directories.
Backups: when Backup original image is enabled in Basic Settings, Directory Squeeze writes a .bak file next to each image (photo.bak.jpg). With Direct WebP on, those backups are WebP as well (photo.bak.webp). Existing *.bak.* files are skipped when scanning, so backups are never re-compressed.
To undo: click Restore backups in selected folders. Each .bak file overwrites its live twin in place, and the .bak is removed after a successful restore.
9.2. Bulk Squeeze from a Page (Premium Only)
This feature allows users to compress all images from a specific page on the website, such as single posts/pages, taxonomy pages (categories, tags, custom taxonomies), archive pages (author archives, date archives, etc.).
Exceptions: Drafts, trashed and private pages are excluded from bulk squeezing.
Note, if your site is using a CDN, you must provide the CDN URL in the Basic Settings for proper image retrieval.
From Squeeze Bulk Tools (recommended)
Go to Media → Squeeze Bulk Tools.
Open the Squeeze from a page block.
Search for a page by title, select it, then click Squeeze from this page.
Squeeze fetches images from that page and compresses them in your browser (progress shows on the same Bulk Tools page).
Free users see the same block locked (URL field preview + Unlock with Premium). Premium unlocks the page search and Squeeze from this page button.
From the front-end admin toolbar (still available)
Login as Administrator to your site. Make sure the admin’s toolbar is enabled. You can enable it in your User Profile’s options (/wp-admin/profile.php):
Navigate to the page on your site, where you want to bulk squeeze images from.
At the admin’s toolbar hover the Squeeze menu and click Squeeze images from this page.
You will be redirected to the page where you can see the process of fetching and compressing your images from the page.
9.3 Bulk savings
Squeeze stores before/after size totals per Media Library attachment when images are squeezed.
Bulk page shows Total saved (since version 1.8.0) — older squeezes have no data.
Completion popup shows that run’s savings (or “Processed N images”).
Restore clears that attachment’s contribution.
Directory Squeeze counts toward the run total only.
10. Backup and Restore Images
To enable the backup option, navigate to Settings → Squeeze, under the Basic Settings tab check the Backup original image option. Click On the Save button at the bottom of the page.
After backup is enabled, it allows you to restore an image to its original state before compression.
The Restore original button is available for the images, which have a backuped original image. You will see it in the same place where the Squeeze button was.
In the Grid mode of the Media Library click on the image and find the Squeeze section, then click on the Restore original button:
In the List mode of the Media Library you will see the Restore original button under the Squeeze column for each image which have a backup:
Restoring Directory Squeeze backups
Images squeezed through Directory Squeeze are not always Media Library attachments, so they use their own restore path: select the folders on Media → Squeeze Bulk Tools and click Restore backups in selected folders. The restore is in place — the live file is overwritten from .bak, and the .bak is deleted once it succeeds. Media Library images still use Restore original on the attachment.
11. Additional Options
There are some additional features you may need.
Delete Backup Image
Remove the backup file to free up storage space.
This action is irreversible, so ensure you no longer need the original version before deleting.
With Direct WebP, the backup you are deleting is the .bak.webp file.
To delete backup of the image:
Navigate to Media → Library.
Switch to the List mode:
Select images of which you want to delete backups.
In the Bulk actions dropdown select Delete Backup Image and click on the Apply button.
Delete WEBP Images
Allows you to remove all WEBP versions of images that were generated by the plugin.
This is useful if you decide to stop using WEBP images or free up server space.
To delete WEBP images do the following:
Navigate to Media → Library.
Switch to the List mode:
Select images of which you want to delete WEBP versions.
In the Bulk actions dropdown select Delete WEBP Image and click on the Apply button.
Filter Images by Non-Squeezed in Media Library
Easily identify images that have not been compressed yet.
Navigate to Media → Library, and use the Non-Squeezed filter to list all uncompressed images.
Available both in the List and Grid modes:
Failed compression (“larger than original”)
If compression would increase file size, Squeeze may leave the original and show a warning with Restore / Re-Squeeze. Changing compression settings clears the failed state so you can retry.
Server delivery — keeps URLs; .htaccess serves WebP to supporting browsers. Premium CDN URL helps map CDN paths for all modes.
Is it safe to replace images with WEBP?
Yes! It’s perfectly safe, especially for new uploads. For existing images, the Squeeze plugin can automatically update JPG/PNG image URLs to their WebP versions when available.
Just a quick note — this replacement happens only when the page loads, so your database isn’t changed. If you deactivate the Squeeze plugin, some images may stop showing. To fix that, simply reselect those images from the Media Library.
Will my images break if I deactivate the plugin?
If you deactivate Squeeze while the Direct WebP option is enabled, some images may stop showing because their JPG/PNG versions were converted to WebP. To fix that, simply reselect those images in your posts or pages to restore the correct URLs.
Why am I seeing an alert “Image conversion blocked by browser privacy setting”?
That means your browser is blocking access to canvas image data (this prevents image conversion).
The privacy.resistFingerprinting setting (or similar privacy features) is enabled.
What you can do:
Open about:config in Firefox and set privacy.resistFingerprinting to false, then restart Firefox.
Use a different browser (Chrome, Edge) or a browser profile without this setting.
WEBP not being served? Ensure a WebP delivery mode is selected. If you see that Apache mod_rewrite is not available, use Direct WebP or Rewrite <img> src instead of Keep JPEG/PNG URLs — server serves WebP.
How to fix a “Request timed out” error? Navigate to the plugin’s setting page (Settings → Squeeze).
At the “Basic Settings” tab increase the value of the field “Squeeze timeout”. By default it equals 60 seconds, try to make it bigger. If the error still persists, that means the script cannot process your image.
“Image too large for this device’s available memory” Compression runs in your browser, so very large images are limited by the device’s RAM, not your server. Squeeze reuses a Web Worker, loads only the codecs a job needs, and forces single-threaded AVIF encoding on low-memory devices. From 1.8.0, Squeeze soft-caps megapixel / “huge” images. For very large Media Library uploads, after-upload thumbnail re-squeeze may be skipped; the attachment is still marked as client-compressed, and in sidecar WebP mode Squeeze may still write the full-size WebP sidecar. If you still hit memory limits: squeeze one image at a time, close other tabs, use a desktop, or set Max image width / height (Premium).
Form submit seems stuck after choosing a photo Squeeze may be optimizing (“Compressing the image…”). Wait; submit is gated until it finishes. Disable Squeeze form uploads only to rule the feature out.
Gutenberg uploads are not being squeezed on WordPress 7.1 Check that Squeeze on upload is enabled. While it is on, Squeeze disables core’s client-side media processing so its own pipeline runs. HEIC/HEIF files are never squeezed.
Using WebP Express? WebP Express conflicts with the rewrite and server-delivery modes. Switch to Direct WebP (the conflict notice disappears once Direct WebP is on) or deactivate WebP Express.
12.2 Frequently Asked Questions
How does the plugin work? The plugin uses client-side compression algorithms and provides you with the ability to compress images in your WordPress media library or during the image upload process.
What does the speed of image compression depend on? Because the compression process happens directly into your browser – it depends on your device’s performance.
How are the images processed? Are they sent to an external server? The images compressed directly in your browser – means no external server used. Squeeze does all the work locally. So you should not worry about privacy.
Which scripts are used for compressing and converting images? The Squeeze plugin utilizes the same scripts and libraries that power the Squoosh.app, an open-source project by the Google Chrome team. These include highly efficient image processing libraries such as:
MozJPEG: Used for compressing JPEG images.
Browser Image Compression: Used for compressing PNG images.
WebP: Used for converting and compressing images to the modern WEBP format.
AVIF: An advanced codec for creating lightweight and high-quality AVIF images.
Why should I use image compression on my website? Image compression helps improve your website’s performance by reducing the file size of images without significantly impacting their quality. Smaller image files load faster, resulting in faster page load times and a better user experience. Additionally, compressed images consume less bandwidth, which can be beneficial for websites with limited hosting resources or mobile users with limited data plans.
Which image formats does the Squeeze plugin work with? The Squeeze plugin supports JPG, PNG, WEBP and AVIF image formats.
Can I compress multiple images at once? Yes, the plugin provides a bulk compression feature. This saves time and effort compared to compressing images individually.
Can I compress images NOT from the Media Library, but from a custom folder? Yes, you can compress images from any folder within your WordPress installation.
Can I customize the compression settings? Yes, the plugin allows you to customize various compression settings according to your preferences. The Settings page is located at Settings → Squeeze.
Does Squeeze work with WP Offload Media (WP Offload S3 / AS3CF)? Yes. Squeeze can compress CDN-hosted images (including when local files are removed). Converted files can sync to S3, GCS, DigitalOcean Spaces, and similar providers.
Recommended — Direct WebP: Converts the file in place to .webp. WP Offload Media then uploads it to your bucket/CDN automatically.
Not compatible — Rewrite <img> src to WebP URLs in HTML: WebP sidecars live in a local squeeze-webp/ folder and are not pushed to external storage, so they cannot be served from your CDN URL.
Not compatible — Keep JPEG/PNG URLs — server serves WebP (.htaccess): Apache rewrite rules only apply to requests that hit your origin. Offloaded image URLs point at the CDN and never pass through .htaccess.
When WP Offload Media is active, Squeeze shows these warnings in WebP delivery settings and recommends Direct WebP.
Can I exclude images from compression? Yes. Under Settings → Squeeze → Basic Settings → Exclusions, list URL or filename patterns (one per line). Full URLs and partial strings are both allowed. Excluded images are skipped during upload squeeze, Bulk Squeeze, and the Media Library Non-Squeezed filter.
Does Squeeze work with the Voxel theme? Yes (free). With Squeeze on upload enabled, pre-upload compression runs on Voxel create-post and file/gallery AJAX uploads, so images are smaller before they reach the server.
Does Squeeze work with Elementor? On-upload squeeze in Elementor is a Premium feature. The free version supports Gutenberg, GenerateBlocks, and Voxel.
Does Squeeze work with GenerateBlocks? Yes. GenerateBlocks media blocks support the same on-upload squeeze as the core Image block when Squeeze on upload is enabled under Basic Settings.
Does Squeeze work with FileBird? Yes. Squeeze is compatible with the FileBird media folder plugin. Bulk and attachment squeeze work with FileBird-organized libraries.
What happens if the squeezed file is larger than the original? Squeeze can skip replacing an upload when the compressed file would be larger (common with already-optimized PNGs). In the Media Library you may see a warning with Restore and Re-Squeeze. Lower JPEG/WebP/PNG quality in the format tabs, exclude the asset under Excluded images, or change settings and try again.
Which scripts are used for compressing and converting images? The Squeeze plugin uses the same technology family as Squoosh.app by the Google Chrome team, including: MozJPEG — JPEG compression Browser Image Compression — PNG compression WebP — converting and compressing images to WebP AVIF — lightweight, high-quality AVIF images Compression runs in your browser via Web Workers. Images are not sent to an external optimization server.
Does Squeeze work with Instant Images? Yes. With Squeeze on upload enabled, stock photos imported through Instant Images are squeezed right after they are attached to the Media Library — using your backup, Direct WebP, and thumbnail settings. This works on the Media Library page, in the media modal, and in the editor sidebar.
Does Squeeze work with WordPress 7.1 client-side media processing? Yes. While Squeeze on upload is enabled, Squeeze turns off WordPress 7.1’s built-in browser image processing so Gutenberg uploads use Squeeze quality, Direct WebP, backups, and thumbnail overwrite. Turn Squeeze on upload off to use core’s pipeline instead (HEIC conversion, HDR thumbnails). Bulk and manual squeeze keep working either way.
Can I undo a Directory Squeeze? Yes, if Backup original image was enabled when you ran it. Select the same folders and click Restore backups in selected folders.
Does Squeeze work on WordPress multisite? Yes, on standard multisite installs — each site has its own Squeeze settings and Media Library. Test Direct WebP on a staging subsite before converting a large network.
Which formats are not supported? Squeeze handles JPEG, PNG, WebP, and AVIF. HEIC/HEIF and GIF files are not squeezed.
