Bulk Image Compressor
Compress and resize many images at once, entirely offline.
Every image is decoded, resized and re-encoded by your own browser — nothing is uploaded. Compression is lossy and permanent, so keep your originals.
About this tool
Drop in a batch of images, set a quality level and a maximum width, and get them all back compressed — as a zip if there are several. Every image is processed by your own browser, so nothing is uploaded and there is no file-count limit imposed by a server.
How to use it
- Drag in your images, or click to browse.
- Set the quality and an optional maximum width or height.
- Download them individually, or all at once as a zip.
Choosing a quality setting
Quality is a 0–100 scale, and the useful range is narrower than it looks.
| Setting | Result |
|---|---|
| 90–100 | Much larger files, no visible gain over 85 |
| 75–85 | The sweet spot for photographs |
| 60–75 | Fine for thumbnails and backgrounds |
| Below 60 | Visible artefacts on most images |
At 80, photographs typically shrink 40–80% with no difference you can see at normal viewing size.
Flat graphics behave differently. Screenshots, logos, diagrams and line art have hard edges, and lossy compression produces visible ringing around them. These often compress better as PNG, and look far worse as JPEG at any setting. Compress photographs; leave interface screenshots as PNG.
Resizing saves more than quality does. A 4000px-wide photo displayed in a 800px column is carrying 25 times more pixels than it needs. Capping the width is almost always the bigger win — drop the max width first, then tune quality.
What happens to your originals and metadata
Compression is permanent. JPEG and WebP discard information to save space, and re-encoding an already-compressed image compounds the loss. Always keep your originals somewhere — the tool never modifies the files you drop in, but once you have replaced them on disk there is no undo.
Re-compressing repeatedly degrades images. Each pass throws away more detail. If you need a different size later, go back to the original rather than resizing the compressed copy.
EXIF metadata is dropped. Canvas gives back pixels, not metadata, so camera settings, copyright tags, and GPS coordinates do not survive. For web use this is usually a feature — publishing a photo with home coordinates embedded is a real privacy problem. For an archive or anything needing provenance, it is a loss, so keep originals.
Orientation is applied, not lost. Phone photos often store a rotation flag rather than rotating the pixels. The browser applies it during decoding, so the output is correctly oriented with the flag no longer needed.
Frequently asked questions
- How much smaller will my images get?
- Typically 40 to 80 percent for photographs at quality 80, often with no visible difference. Screenshots and flat graphics compress less well as JPEG or WebP — for those, consider keeping PNG.
- Is quality loss reversible?
- No. JPEG and WebP compression discards data permanently, so always keep your originals. The preview lets you compare before committing.
- How many images can I process?
- As many as your device's memory allows — 50 at a time is comfortable on most machines. Since processing is local, there is no upload limit or queue.