How to compress an image
- Drop one or more images, paste one with Ctrl+V, or click Choose files.
- Keep quality at 75 for photos and choose a Max size if the images are large.
- Click Compress and download each file or all of them as a ZIP.
How it works
Each image is decoded and saved again as JPG or WebP at the quality you choose. Lower quality throws away fine detail the eye barely notices, which is where most of the savings come from. Setting a Max size shrinks the dimensions too; a 4000-pixel phone photo reduced to 1920 px has less than a quarter of the pixels.
If the result would be bigger than your original, for example a file that was already well compressed, the original is kept and marked as such. You never get a heavier file back.
What we measured
We compressed 9 public JPG sample photos from the scikit-image project (1,133 KB in total) at quality 75 in Chrome on a 4-core test computer. They came to 550 KB, 51 % smaller, in 0.22 seconds.
Saving the same photos’ PNG versions (6,072 KB) as JPG at quality 75 brought them to 550 KB. PNG is lossless and large for photos, so converting is where the biggest wins are.
When to use it
Fitting attachments under an email limit. Meeting the KB limits of job applications and government forms. Speeding up a website or blog, since smaller images load faster and page speed affects user experience. Saving space before backing up photos.
Need exact dimensions too? Use Bulk Image Resizer first. To put the compressed photos in one file, continue with Image to PDF.
Limits
- Compression is lossy: each re-save loses some detail, so keep your originals.
- PNG has no quality slider in browsers. A PNG kept as PNG only gets smaller when its dimensions shrink.
- Transparent areas become white when saved as JPG. Choose WebP to keep transparency.
- Metadata such as GPS location and camera model is not copied to the new file.
Frequently asked questions
Are my images uploaded?
No. Compression happens in your browser with the canvas API; the files stay on your device.
What quality should I use?
75 suits most photos. Go to 85 or higher for images with text or sharp lines, or 60 when size matters more than detail.
Why didn’t one file get smaller?
It was already compressed more than the settings would achieve, so we kept the original. Try a lower quality or a smaller max size.
JPG or WebP?
WebP is usually smaller at similar quality and supports transparency. JPG opens everywhere, including old software and some upload forms.