How to use the image compressor
- Drop images onto the drop zone or click to choose them (JPG, PNG or WebP, up to 100 at once).
- Choose the output format. "Keep format" keeps JPEG and WebP, and turns PNG into WebP because PNG has no quality setting.
- Set the quality. 70 to 80 is a common starting point for photos.
- Optionally limit the longest side, for example to 2000 pixels, which often saves more than lowering quality.
- Click Compress, compare with the slider, and download files one by one or as a ZIP.
Worked example
A 4000 x 3000 phone photo for a website
Limiting the longest side to 2000 pixels makes it 2000 x 1500, a quarter of the pixels, before quality is applied. The tool then shows the exact before and after size for each file. If a compressed JPEG ends up larger than the original, the original is kept.
How it works
Each image is decoded by the browser, optionally downscaled with repeated halving and high quality smoothing, and re-encoded with the browser's JPEG or WebP encoder at your quality setting. Transparent pixels are filled with white only when saving as JPEG, which has no transparency.
Assumptions
- Quality numbers are not comparable between browsers or between JPEG and WebP; judge the result visually.
- Re-encoding removes EXIF metadata, including camera details and GPS location.
Frequently asked questions
Are my files uploaded?
No. Images are processed in your browser on your own device and are never sent to our server. The page keeps working if you go offline after it loads.
Is compression lossless?
No. JPEG and WebP compression here is lossy: some detail is discarded to make files smaller. Use the comparison slider to check that the result looks right, and keep your originals.
Why is my compressed image larger?
Images that are already well compressed, or small graphics, can grow when re-encoded. The tool keeps the original when a same-format output is not smaller, and warns you when a converted file is larger.
What happens to transparency?
WebP keeps transparency. JPEG cannot store it, so transparent areas are filled with white and the tool warns you.
Can I compress to an exact file size?
No. File size depends on image content, so the tool does not promise a target. Lower the quality or the maximum dimension and compare the sizes shown.
Limitations
- Images up to 50 MB each are accepted. Very large images (tens of megapixels) depend on device memory, and iPhones and iPads limit canvases to about 16.7 megapixels.
- Output quality depends on your browser's encoder, so results vary slightly between browsers.
- Animated GIFs and animated WebP images are not supported.
- Older Safari versions cannot save WebP; choose JPEG there.