Image Format Converter
Convert PNG, JPEG, WebP, and AVIF locally with quality and before-after byte comparisons
Images are re-encoded locally. JPEG fills transparency white; PNG ignores quality; animation becomes one frame. Original metadata is not retained, and output can grow.
Format comparisons will appear here.
About this tool
Convert up to 20 PNG, JPEG, WebP or AVIF images to one selected output format. Every result shows its dimensions, source bytes, output bytes and output-to-input percentage; values above 100% mean the new file is larger. PNG, JPEG and WebP use browser encoders, with unsupported formats reported as errors instead of mislabeled PNG files. AVIF output uses a local libavif WebAssembly encoder; AVIF input uses native browser decoding when available and falls back to WebAssembly. PNG ignores quality. JPEG composites transparency onto white; PNG, WebP and AVIF can retain alpha. All conversions re-encode decoded pixels, keep one frame, and omit original EXIF, GPS, ICC and arbitrary metadata. Browser color conversion and reduced bit depth can change pixels even when exporting to PNG. Setting or file changes clear the old batch. Download each file or a ZIP with unique names, and compare visual quality in the destination application. Each input must be at most 40 MiB, with no edge above 8192 pixels and no more than 32 million pixels. Files are processed in this tab and are not saved as browser drafts.
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
Does conversion reduce file size?
Not always. The output-to-input percentage can exceed 100%, especially when converting photographs to PNG.
Will JPEG keep transparent corners?
No. JPEG has no alpha channel; this tool fills transparent pixels with white. Choose PNG, WebP or AVIF when alpha is needed.
Why does PNG ignore quality?
The PNG encoder preserves the rendered canvas pixels without a lossy quality setting. Decoding and color conversion may already have changed the source values.
Are animations and original metadata preserved?
No. The converted file contains one frame and does not copy original EXIF, GPS, ICC profiles or arbitrary metadata.
How is AVIF handled?
Encoding uses a local WebAssembly codec. Decoding prefers the native browser and uses WebAssembly when native decoding fails.
What happens after changing the target format?
Old results disappear. Convert again to create a batch whose bytes, MIME types and filename extensions all match the new settings.
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