Image compressor batch-compresses photos to WebP, AVIF, JPEG XL, JPEG, PNG, and other formats with full control over encoding parameters. Everything runs in the browser using WebAssembly — there is no file size limit and images are never uploaded to a server.
Format quality ranges and what to expect
WebP (quality 0–100, method 0–6): Quality 80 typically produces files 25–35% smaller than equivalent JPEG. The method parameter trades encoding time for file size; method 6 is slowest but smallest.
AVIF (quality 0–100, speed 0–10): Quality 60 AVIF is usually visually equivalent to JPEG quality 80+ while being significantly smaller. Lower speed values give better quality at the cost of encoding time.
JPEG (quality 0–100): Daily use sits at 75–85. Enable "Optimize Huffman table" for additional size reduction without quality loss.
JPEG XL (quality 0–99.9, effort 1–9): Quality below 7 disables the lossless fallback mode. Use effort 9 only when file size is critical and you have time to wait.
OxiPNG (effort 0–6): Lossless PNG re-compression. Higher effort means smaller file but longer encoding.
Choosing a format
Web images (prioritize size)
- AVIF or WebP for photos — smallest file at same quality
- OxiPNG when lossless is required (icons, UI assets)
- Fall back to JPEG/PNG for older browser compatibility
Archival and print
- JPEG XL for high-quality lossless or near-lossless
- WebP lossless mode for images with transparency
- Already-optimized files may increase in size when recompressed — that is expected
Resize options
When resizing is enabled, width and height are in pixels. The fit modes behave as follows: contain scales to fit within the box without cropping; cover scales and crops to fill the box; fill stretches to exact dimensions ignoring aspect ratio; inside and outside scale only when the image is larger or smaller than the target, respectively. Lanczos3 is the default resize algorithm and produces the sharpest results for downscaling.
Reading the results
A green percentage means the file shrank. A red percentage means the compressed file is larger than the original. This is normal when converting a heavily optimized JPEG to a lossless format like PNG, or when the source is already well-compressed and the output settings are conservative. Lowering quality or switching to a more efficient format resolves most size increases.