Image Compressor

No — the compressor runs entirely in your browser. Your image is decoded, re-encoded at your chosen quality and downloaded on your own device — it is never sent to a server, logged or stored. That makes it safe for private photos, screenshots and confidential graphics, and it keeps working offline once the page has loaded. Closing the tab clears everything.

How much an image shrinks depends on the image itself and the quality you pick. Photos typically shrink by 40 to 80 percent at a quality of 70 to 85 with little visible loss, while images that are already compressed may shrink less. After each run the tool shows the original size, the new size and the exact percentage saved so you can nudge the slider until the trade-off feels right.

JPG and WEBP are lossy formats, so lowering the quality slider removes fine detail to save space. At 80 to 90 percent the difference is usually invisible; below about 60 percent you may start to see softening or blocking, especially around text and sharp edges. Preview the result before downloading and raise the quality if it looks too soft. The pixel dimensions are always kept — only the file size changes.

Not with JPG or WEBP — those are lossy formats, so reducing the file always discards a little detail, although at 80 to 90 percent quality it's invisible to the eye. True lossless compression means keeping a lossless format such as PNG, where the pixels are preserved exactly and the file still shrinks, just by less. So you have two honest options: compress at high quality for no visible loss, or stay lossless for no loss at all and accept smaller savings. Preview the result before downloading and raise the quality if anything looks soft. We measured how much quality that actually costs across JPEG and WebP in our compression study.

Yes — because PNG is lossless, the biggest savings come from re-encoding it as WEBP (which keeps transparency) or JPG (which does not). The compressor defaults a PNG to WEBP for this reason. If you specifically need the file to stay a PNG, the file-size reduction will be smaller — resizing the dimensions with the Image Resizer is often the better lever there.

No — the pixel dimensions are unchanged. Compression keeps the width and height exactly the same and only changes how the pixels are stored, so the image still fits wherever it did before. If you also want fewer pixels — for example to fit an upload limit or a layout — resize it first with the companion Image Resizer, then compress.