Settings reference
BytCrush → Settings. Changes apply once you click Save changes in the bar at the bottom. The button stays greyed out until you change something, and the browser warns you if you leave with unsaved changes.
Reset to recommended puts the default values back into the form. Options that are greyed out are left alone. Nothing is saved until you click Save changes.
Settings only affect images optimized from then on. To apply new settings to images that are already optimized, use Re-optimize on each image in the Media Library (see Dashboard), or Restore all and then Optimize all images again.
Compression level
Pick one card. JPEG quality is never raised above the original's, and a file is never replaced by a bigger one.
| Level | Plan | JPEG | WebP | AVIF | Notes |
|---|---|---|---|---|---|
| Gentle | Free | 88 | 88 | 72 | Visually lossless. Smallest savings, zero visible change. No chroma subsampling. WebP copies of PNGs are lossless. |
| Balanced (default, Recommended) | Free | 80 | 80 | 60 | Big savings with no noticeable quality loss. 4:2:0 chroma subsampling for JPEG. |
| Ultra | Pro | 70 | 70 | 50 | Maximum savings for speed-critical sites. PNGs become palette images. See Pro. |
For every level:
- JPEGs are saved as progressive JPEGs.
- PNGs are recompressed losslessly at maximum compression (Ultra also reduces opaque PNGs to 256 colours).
- GIFs keep their original file. They only get WebP and AVIF copies.
- Animated GIFs and animated PNGs are left untouched.
The Ultra card only appears when Pro is active. If Pro is no longer active, a site set to Ultra uses Balanced.
Next-gen formats
Modern formats are created alongside each image (photo.jpg → photo.jpg.webp) and served to browsers that support them. Your originals stay untouched.
The badges at the top show whether your server can create WebP and AVIF, and which image library is in use.
| Setting | Default | Plan | What it does |
|---|---|---|---|
| Create WebP versions | On | Free | Creates a WebP copy of each JPEG, PNG and GIF file. A copy is only kept if it's smaller than the optimized original. Greyed out if the server can't create WebP. |
| Create AVIF versions | Off | Free | Creates an AVIF copy of each JPEG, PNG, WebP and GIF file. It's kept only if it's smaller than both the optimized original and the WebP copy, and it's served first to browsers that support it. Encoding is slower than WebP. Greyed out if the server can't create AVIF. |
| Delivery method | Picture tags | Free | How visitors receive the WebP/AVIF copies: Picture tags (Works on every host and CDN), Server rewrite (Needs Apache or LiteSpeed, or Apache/LiteSpeed detected) or Off (Create files only). See WebP and AVIF delivery. |
When Server rewrite is chosen but can't work, a yellow warning appears at the top of the screen:
- This server is not Apache or LiteSpeed, so .htaccess rules will be ignored. Use Picture tags instead.
- The uploads folder is not writable, so the rewrite rules could not be saved.
Turning a format off doesn't delete existing copies straight away. Each image's copies are removed the next time it's optimized or restored.
Size & quality
| Setting | Default | Plan | What it does |
|---|---|---|---|
| Resize oversized originals | On | Free | Scales the main image down to fit within Max width × Max height, keeping the aspect ratio. Never upscales. Only the main file is resized, not the sizes WordPress generates. |
| Max width / Max height | 2560 px / 2560 px | Free | Shown while resizing is on. Accepts 320 to 10000 px. |
| Smart target file size | Off | Pro | Aims for a maximum file size for each image's main file. See Pro. |
| Target size | 250 KB | Pro | Shown while Smart target file size is on. A slider from 50 to 1000 KB, with presets 100 KB · blogs & news, 200 KB · stores and 500 KB · photography. |
| Strip metadata | On (Recommended) | Free | Removes camera EXIF, GPS location and editing history from every file and its WebP/AVIF copies. The colour profile is kept, and the photo is rotated upright first so it never turns sideways. |
On the free plugin from WordPress.org, the Smart target file size row isn't shown. In the Pro plugin without an active license, it's shown greyed out with a PRO badge.
With GD instead of Imagick, files never keep metadata or a colour profile, whatever Strip metadata is set to. See FAQ.
Automation & safety
| Setting | Default | Plan | What it does |
|---|---|---|---|
| Optimize new uploads automatically | On (Recommended) | Free | Every image you upload is optimized as soon as WordPress has created its sizes. |
| Optimize in the background | On | Free | Optimize all keeps running on your server after you close the tab. If your host blocks the background requests, an open dashboard tab finishes the job instead. With it off, the dashboard tab runs the job and must stay open. |
| Keep original images | On (Recommended) | Free | Stores a private, byte-for-byte copy of every file before it's changed, in uploads/bytcrush-backups-…/. The description shows the exact folder name. See Backups. |
| Delete all data when uninstalling | Off | Free | When the plugin is deleted, also removes its settings, statistics, the WebP/AVIF copies and the stored originals. Run Restore all first if you want your originals back. See Backups. |
When Keep original images is off, a warning appears under it: Without backups, optimizations cannot be undone. Images you optimize from now on will have no original to restore. Images that were already backed up keep their backups.
Settings on other screens
The three automatic fixes of the page speed audit (Responsive sizes, Missing width & height, Lazy-load offscreen images) are switched on and off on the Page audit screen, not here. They're Pro features and all off by default. See Pro.