About Compress Image
Compressing an image trades a small amount of visual information for a much smaller file. It is how a 4 MB phone photo becomes a 300 KB web image that still looks identical on screen. This tool compresses JPG, PNG and WebP files in batches inside your browser, can resize them at the same time, and reports exactly how many bytes you saved.
How to use
- Choose or drag in the images you want to compress — as many as you like.
- Set the quality; 70 to 80% is invisible for most photographs.
- Optionally change the output format, or cap the width to shrink oversized images further.
- Compress, check the saving, and download files individually or as a ZIP.
What the quality slider does
JPEG and WebP work by transforming the image into frequency components and storing the ones the eye notices most precisely, while rounding away the rest. The quality setting controls how aggressively that rounding happens. Small changes at the top of the range cost very little visually and save a great deal of space.
Between 70 and 85% almost nobody can pick the compressed version out of a line-up of photographs, while files typically drop by half or more. Below about 50%, artefacts start to appear: blocky patches in flat areas of sky, and coloured fringing around sharp edges.
Content matters as much as the number. Photographs with soft gradients and texture compress beautifully. Screenshots, logos and anything with crisp text degrade visibly at settings that leave a landscape photo untouched — for those, keep the quality high or stay with a lossless format.
Getting a bigger saving
Resizing usually beats compressing. A 4000-pixel photo displayed 800 pixels wide is carrying twenty-five times the pixels it needs; capping the width to 1920 or 1280 removes most of the file before quality even enters the picture. The width control here applies that reduction in the same pass.
WebP output is the other easy win, generally landing a quarter to a third below JPEG at matched quality, with support in every current browser. Choose it whenever the destination is a web page rather than an email attachment or a print shop.
PNG is lossless, so the quality slider does nothing when the format is kept. The saving on a PNG comes from resizing and from stripped metadata alone — if a PNG photograph needs to be much smaller, converting it to JPG or WebP is the real answer.
Compressing without wrecking your originals
Lossy compression is not reversible. What it removes cannot be recovered by raising the quality later, and re-compressing an already-compressed file compounds the damage — the generation loss that makes an image forwarded through five apps look soft and blotchy.
Work from originals and treat compressed files as disposable output. Compress once, from the highest-quality copy you have, for each place the image needs to go.
Re-encoding also strips EXIF metadata, which includes any GPS coordinates recorded when the photograph was taken. That is worth knowing in both directions: it removes location data before you post a picture publicly, and it removes camera settings and copyright fields you may have wanted to keep.
Frequently asked questions
What quality setting should I use?
Around 75% for photographs on the web — usually indistinguishable from the original at roughly half the size. Push to 85 to 90% for images with text or sharp graphics, which show artefacts sooner.
Why did my PNG barely get smaller?
PNG is a lossless format, so the quality slider has no effect while the format is kept. Reduce the width or convert to JPG or WebP for a real reduction.
Does compressing an image reduce its dimensions?
Not by itself — compression changes how the pixels are stored, not how many there are. Use the resize option in the same pass if you want fewer pixels too.
Are my images uploaded to a server?
No. Compression runs in your browser and the results are written straight to your downloads folder, so the photographs never leave your device.