How to compress an image
Drop JPG, PNG or WebP images into the box above, or click Choose files.
Choose a quality level. 75% is a strong default for photos; use 85–90% for images with text or fine detail.
Optionally change the output format. WebP usually gives the smallest files.
Click Compress images, compare the sizes, and download the results one by one or as a ZIP.
Why compress images?
Images are usually the heaviest part of a web page. Compressing them makes pages load faster, improves Core Web Vitals, and reduces hosting and bandwidth costs.
Smaller files are easier to share, too: they fit under email attachment limits, upload faster on mobile data and take less space in cloud storage.
Photos straight from a phone or camera are saved at very high quality. Much of that data is detail you can't see on a screen, so they can often be cut in half or more with no visible difference.
Lossy vs lossless compression
Lossy compression removes detail that's hard to see. That's how JPG and lossy WebP work, and the quality slider controls how much is removed. For most photos, visible artifacts only start to appear somewhere below 60–70%.
PNG is a lossless format, so it's compressed differently: the image is reduced to an optimised palette of up to 256 colours with subtle dithering, then saved as a PNG with its transparency intact. Popular PNG optimisers use the same technique, and it often cuts screenshots, illustrations and interface graphics by more than half.
If a compressed file would come out larger than your original, which can happen with images that are already optimised, the original is kept so you never download a bigger file.
| Property | Lossy (JPG, WebP) | Palette (PNG) |
|---|---|---|
| How it saves space | Discards fine detail | Reduces the number of colours |
| Best for | Photos | Screenshots, graphics, logos |
| Transparency | WebP only | Yes |
| Quality slider controls | Compression strength | Size of the colour palette |
Is it safe?
Yes. Compress Image runs entirely in your browser. Your files are read and converted by your own device using built-in browser technology, so they are never uploaded to a server and nobody else can see them.
You can check this yourself: open your browser's developer tools, switch to the Network tab and convert a file. No upload requests are made.
Compressed images are rebuilt from their pixels, so EXIF metadata such as location, camera model and capture time is removed. If the original is kept because it was already smaller, it is returned unchanged.
Files stay in this tab's memory only until you remove them or close the page.
Frequently Asked Questions
How much can I compress an image?
Photos from phones and cameras often shrink by half or more at 75% quality with no visible difference. Images that were already optimised may only shrink a little. The result shows the exact saving for each file.
Does compressing change the image dimensions?
No. The width and height stay the same. To make an image smaller in pixels, use Resize Image.
How does PNG compression work here?
PNGs are converted to an optimised palette of up to 256 colours with dithering, then saved as PNG with transparency preserved. Lower quality settings use fewer colours and give smaller files.
What if the compressed file is bigger than the original?
Then you get the original file back unchanged, marked as already optimised.
Should I switch to WebP?
If the images are for a website, yes. WebP is usually the smallest option for both photos and graphics, and every modern browser supports it. Choose WebP under Output format.
How many images can I compress at once?
Up to 25 images per batch, each up to 50 MB. Download them individually or together as a ZIP.