Image Format Converter
Convert PNG, JPEG, WebP, and AVIF locally with quality and before-after byte comparisons
AVIF uses browser-side libavif WASM; files remain local.
Format comparisons will appear here.
About this tool
Image Format Converter changes PNG, JPEG, WebP, and AVIF files between supported raster formats without uploading them. Multiple files can share one target format and quality setting. Each result reports pixel dimensions, original bytes, output bytes, and the output-to-input percentage, with individual or ZIP downloads. Standard formats use browser Canvas encoders; AVIF input and output use libavif WebAssembly so AVIF conversion does not depend on inconsistent Canvas encoder support. Re-encoding does not preserve EXIF, GPS, animation, ICC profiles, or every high-bit-depth detail. JPEG removes transparency, while PNG can be much larger for photographs. Compare visual output in the target application rather than choosing only the smallest byte count.
Scenario Recipes
Compare WebP and AVIF output for a product photo set
Goal: Choose a delivery format using visual quality and bytes together
- Convert a small representative batch to WebP at the approved quality and record result sizes.
- Repeat with AVIF using the same source pixels, then inspect edges, gradients, text, and transparency.
- Test both formats in the supported browser matrix and choose a fallback strategy before converting the full library.
Result: A format decision based on real assets, browser support, visual review, and byte savings.
Frequently Asked Questions
Which conversions are supported?
PNG, JPEG, WebP, and AVIF can be decoded and re-encoded to any listed target format.
Will JPEG keep transparency?
No. JPEG has no alpha channel; transparent pixels are flattened by the Canvas output.
Why can PNG be larger than the source?
PNG is lossless and often inefficient for photographs compared with JPEG, WebP, or AVIF.
Does conversion preserve metadata?
No. Re-encoding does not preserve EXIF, GPS, ICC, animation, or arbitrary application metadata.
Is AVIF really encoded locally?
Yes. The tool loads a browser-side libavif WebAssembly codec only when AVIF work is requested.
Are files uploaded?
No. Pixel decoding, encoding, preview, comparison, ZIP creation, and downloads run locally.
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