Compress images without uploading them anywhere
Most online image compressors send your photos to a server you don't control. This one doesn't. Every image you add is read and re-encoded directly inside your browser using the Canvas API, then handed back to you as a download. Nothing is transmitted, logged, or stored - close the tab and it's gone.
How to compress an image in your browser
- Drop one or more images onto the box above (or click to pick files).
- Choose an output format - WebP usually gives the smallest file at the same quality, JPG is the safest for sharing, and PNG keeps transparency.
- Set a quality level. 75-85% is the sweet spot for photos - visually identical, far smaller.
- Optionally cap the width or height to shrink large photos before compressing.
- Click Compress images, then download each result or all at once.
JPG vs WebP vs PNG - which should I pick?
WebP typically saves 25-35% over JPG at the same visual quality and is supported by every modern browser. Use JPG when you need maximum compatibility (email, older apps). Use PNG only when you need a transparent background or pixel-perfect graphics, since it's lossless and larger.
Real-world size targets
Compression is only meaningful against a target. Some numbers that come up constantly: most email providers cap attachments at 20-25 MB total, so a batch of ten photos needs to average under 2 MB each. Job portals and government upload forms often enforce 1 MB or even 500 KB per file. For a web page, keeping the largest image under 200 KB is a common performance budget, because oversized images are the single biggest cause of slow page loads. A modern phone photo starts at 3-8 MB, so in practice you are usually compressing by 80-95%, and at sensible quality settings that is visually invisible on a screen.
Limitations to know
Compression here works by re-encoding the image, so it is lossy by design: run the same photo through five times and quality slowly degrades, so always compress from the original. Screenshots and diagrams with sharp text compress poorly as JPG (edges get fuzzy) - keep those as PNG or WebP instead. And if a file is already heavily compressed, there is little left to squeeze; getting a 100 KB image under 20 KB usually means reducing its dimensions too, which the Image Resizer handles.
FAQ
Does this Image Compressor upload files to a server?
- No. All processing happens locally in your browser. Your files never leave your device.
Is there a file size or count limit?
- No artificial limit - the only constraint is your device's memory. Very large batches are processed one image at a time.
Does it work offline?
- Once the page is loaded it runs without a connection, because the work is done on your machine.
Will compressing reduce quality?
- Lossy formats (JPG/WebP) trade a little quality for much smaller files. At 80% the difference is usually invisible. PNG is lossless.