Compress Image
Reduce image file size with a quality slider and before/after sizes.
How to use Compress Image
- Add the JPG, PNG or WEBP images you want to shrink.
- Pick an output format — JPG for photos, WEBP for smaller files, PNG when you need lossless.
- Set the quality slider; 70–80% is usually indistinguishable from the original.
- Press Compress images and check the before and after sizes on each card.
- Download images individually, or take the whole batch as a ZIP.
How Compress Image works
Image compression trades detail you cannot see for file size you definitely can. This tool gives you the slider and shows you the result, one card per image, with the original and compressed size side by side and a total saving across the batch.
Pixel dimensions never change. A 4000×3000 photo stays 4000×3000 — only the encoding changes. That distinction matters: if you want smaller dimensions rather than a smaller file at the same size, Resize Image is the tool you want, and using both together usually beats pushing either one to an extreme.
Format choice affects the result as much as the slider does. JPG is the reliable default for photographs. WEBP typically produces files 25–35% smaller than JPG at comparable quality and is supported by every current browser. PNG is lossless, so the quality slider is disabled for it — it will faithfully preserve a screenshot or a logo, and it may barely shrink a photograph at all.
Images are processed one at a time rather than all at once, because decoding several full-resolution photos simultaneously is the fastest way to run a browser tab out of memory.
Frequently asked questions
Are my files uploaded to a server?
No. This tool runs entirely inside your browser — the file is read from disk by the page and never transmitted. It keeps working even if you disconnect after the page has loaded.
What quality setting should I use?
Start at 70–80%. For most photographs that is visually indistinguishable from the original at normal viewing size, while cutting the file to a fraction of its size. Below about 50% compression artefacts become visible around sharp edges and in flat areas of colour. Because you see the resulting size per image, it is easy to try a value, look at the preview, and adjust.
Why did my PNG barely get smaller?
PNG is a lossless format, so the quality slider does not apply — it can only pack the same pixels more efficiently. On photographs, which have no large areas of flat colour, there is little to gain and the file may even grow. Choose JPG or WEBP for photographs and keep PNG for screenshots, diagrams and anything needing transparency.
Is EXIF data such as camera settings or GPS kept?
No. Each image is decoded to pixels, redrawn on a canvas and re-encoded, and that process does not carry metadata across. The output has no EXIF block, so camera model, date and any GPS coordinates are dropped. That is worth knowing in both directions: it is a privacy benefit before sharing a photo, and a loss if you were relying on those tags.
Are the image dimensions changed?
No. Every image is redrawn at its exact original width and height, so only the encoding changes. If you want fewer pixels as well — which usually saves far more than compression alone — use Resize Image, either instead of or after this.
How many images can I do at once?
There is no fixed limit, and they are processed one after another to keep memory use predictable. Very large batches of high-resolution photos will take a while, since all the work happens on your own device — the progress bar names each file as it goes.