Image Compressor
Make images smaller without losing quality. Drop multiple files at once and compress them all in seconds.
Drop your images here
or click to browse. Select multiple files
How it works
This re-encodes images at a lower quality setting using the browser's own encoder, on a canvas, in your tab. Drop one image or a batch, pick a preset, download the results. Nothing is uploaded.
The four presets map to quality values of 0.4, 0.7, 0.85 and 1.0. Those numbers go straight to the encoder, so what they do depends on the output format rather than on some universal scale.
More detail
The presets, and where they stop mattering
- Low, 0.4. Visible artefacts on photographs, obvious ringing around text. Fine for a thumbnail, wrong for anything a person will look at closely.
- Medium, 0.7. The usual sweet spot for web images. Hard to distinguish from the source at normal viewing size.
- High, 0.85. Near-transparent on photographs. Use it when the image is the point.
- Lossless, 1.0. Still lossy for JPEG and WebP, just at the encoder's maximum quality. Only PNG is genuinely lossless, and for PNG the setting is ignored entirely.
Things worth knowing
The quality slider does nothing when the output is PNG. PNG has no quality parameter, so the value is not passed to the encoder at all. If a PNG is too big, the fix is fewer pixels or a different format, not a lower quality setting.
Metadata is dropped. The image is decoded to pixels and re-encoded, so EXIF, GPS coordinates and colour profiles do not survive. That is useful if you are stripping location data before posting, and a problem if you needed the camera information.
Re-compressing an already-compressed JPEG compounds the damage. Each pass quantises the previous pass's artefacts. Compress once from the best source you have.
Limits are 50 MB per file, 100 megapixels, and 16384 pixels on any one side. That last one is the browser's canvas ceiling rather than a choice.
Questions
Are my images uploaded?
No. Everything happens on a canvas in your browser. Open devtools and watch the Network tab while you compress: nothing carrying the image leaves the page.
Why did nothing happen to my PNG?
Because the quality setting is not applied to PNG. It is a lossless format and the encoder ignores the value. To shrink a PNG, resize it or convert it to WebP, which will usually be far smaller for the same picture.
Will this strip location data from my photos?
Yes, as a side effect. Re-encoding from pixels discards all metadata, including GPS coordinates and camera details. Worth knowing in both directions: it is good for privacy and bad if you wanted the EXIF kept.
Can I compress several images at once?
Yes. Drop a batch and they are processed one after another in the tab. Very large batches of very large images can exhaust the tab's memory, so split the job if it fails partway.