About the free image compressor
Most online image compressors upload your file to a server, queue it, compress it, and send it back. This one does not. It uses your browser's built-in image codecs to re-encode the picture directly on your device, so a 20 MB photo compresses in about a second, works offline once the page is loaded, and is never seen by us or anyone else. Because there is no server doing the work, there is also no reason to limit you: compress as many images as you want, at any size your device can handle, without an account.
You get two ways to compress. The quality slider re-encodes at a fixed quality level, which is the right choice when you care about how the image looks. The target file size mode runs a binary search across quality levels and returns the best-looking file that fits under your limit, which is the right choice when a form, marketplace, or email server enforces a hard cap like 200 KB. In both modes the pixel dimensions stay untouched; only the encoding changes.
JPG, WebP, or PNG: which output to pick
For photos, WebP is usually 25 to 35 percent smaller than JPG at the same visual quality, and every modern browser and social platform accepts it. JPG remains the safest choice for maximum compatibility with older software and printing services. PNG is lossless, so it never introduces artifacts, but it is also the largest by far and only worth it for screenshots, logos, and graphics with hard edges or transparency. The Auto setting makes this call for you: JPG and WebP files are recompressed in place, while PNG, HEIC, and AVIF inputs are converted to WebP so the file actually gets smaller. If you need a specific format instead, our free image converter handles direct format changes.
What people use it for
The classic jobs: getting a photo under an upload limit for a job application, visa portal, or marketplace listing; shrinking images before sending them over email or messaging apps; and speeding up websites, where oversized images are the single most common performance problem. Photographers use the target size mode to prepare web previews of their work, and developers use it to squeeze assets before shipping. AI artists compress generated images before posting them, since most generators output large PNG files that social platforms will recompress badly on their own. If you also need the image at different pixel dimensions, run it through the free image resizer first, since fewer pixels compress to a smaller file than any quality setting can reach alone.
Compression limits and quality
Compression is a one-way street: once detail is gone, a stronger JPG cannot bring it back. If you have inherited an image that was compressed too hard, blocky, blurry, or full of ringing artifacts, compression tools cannot help, but AI restoration can. Upsampler's premium Creative and Precise Upscale models were trained to remove exactly these compression artifacts while adding back realistic detail, and they handle outputs up to 100 megapixels. For everyday shrinking, though, the free tool above is all you need: it accepts JPG, PNG, WebP, HEIC, AVIF, GIF, and BMP up to 64 megapixels and never adds a watermark.