About Compresso

Compresso is a free tool for making images smaller without a visible loss of quality. It exists because most compressors force a trade-off — smaller files at the cost of a softer, degraded picture — and that trade-off is usually unnecessary.

Our approach is simple but strict: for every image we generate a compressed candidate, then compare it with the original pixel by pixel. If the difference could be seen by eye, the candidate is rejected and a safer one is kept. The result is a smaller file that looks identical to the source.

PNG files are rebuilt with palette quantization and the smallest lossless encoding; JPEGs are re-encoded with mozjpeg; WebP is re-encoded at the optimal point between size and fidelity. Everything runs in memory and is deleted the instant your download is ready — your images are never stored.

Compresso is free to use and kept running by unobtrusive advertising. No account, no upload limits beyond what keeps the service fast for everyone.