Batch Convert Images — JPG · PNG · WEBP
Convert many images at once between formats with full quality control. WEBP for smallest files, PNG for transparency, JPG for universal compatibility.
· Free forever · No registration
Batch image conversion means re-encoding many images between JPG, PNG, and WEBP in a single pass. Resizo's free batch converter runs entirely in your browser using the HTML5 Canvas API — no upload. Pick the output format, set quality (JPG and WEBP only; PNG is lossless), optionally cap the width to shrink files further, and download everything as a ZIP. WEBP is typically 25–35% smaller than JPG at matching quality.
Drop images to convert
or click to browse · JPG · PNG · WEBP · GIF
Format Comparison
| Format | Best For | Transparency | Avg Size |
|---|---|---|---|
| JPG | Photos, social posts | No | Medium |
| PNG | Logos, icons, screenshots | Yes | Large |
| WEBP | Web — best of both | Yes | Smallest (~30% less) |
When to batch-convert image formats
Faster websites
Convert a site's JPG and PNG library to WEBP to cut image payload by 25–35% with no visible quality loss. Directly improves Largest Contentful Paint (LCP) and PageSpeed scores.
Transparency needs
Convert JPGs to PNG (or WEBP) when you need transparent backgrounds — logos, UI assets, product cut-outs. Note: JPG doesn't store transparency, so source transparency must already exist.
Email & messaging
Convert heavy PNG screenshots to JPG at 75–85% quality to fit inside Gmail, Outlook, or WhatsApp limits. Pair with the optional max-width to hit a target file size.
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FAQ
Which format is smallest for the web?
WEBP is typically 25-35% smaller than JPG and PNG at the same visual quality, with transparency support.
Why is the quality slider hidden when I pick PNG?
PNG is lossless. Every PNG is encoded at maximum quality. To shrink a PNG, resize its dimensions or convert to WEBP.
Will converting JPG to PNG improve quality?
No. PNG is lossless but the source JPG already lost detail. PNG only freezes existing quality at a much larger file size.
Are my files uploaded?
No. Conversion runs entirely in your browser. Files never leave your device.