Overview
What this tool does
Convert images between PNG, JPG, WebP, AVIF, and HEIC. Free, in-browser, batch capable. HEIC (Apple's iPhone format that won't open on most laptops) gets decoded right in your browser via WebAssembly. Convert one image at a time or drop a folder and grab everything as a ZIP. Quality slider for the lossy formats (JPG, WebP, AVIF) so you can balance file size vs. fidelity. Nothing uploads anywhere: every byte stays on your device.
How to
Use it in 3 steps
- Drop one or more images. Accepted: JPG, PNG, WebP, AVIF, HEIC/HEIF, BMP, GIF (first frame only).
- Pick your output format. PNG is lossless. JPG/WebP/AVIF are lossy with adjustable quality.
- For lossy formats, drag the quality slider. 80 to 90 is the sweet spot for most photos.
- Click a single Download button per item, or hit Download all to grab everything in a ZIP.
- HEIC files take a moment to decode the first time (the WebAssembly module is ~1 MB).
FAQ
Frequently asked questions
▶Can it open HEIC files from my iPhone?
Yes. HEIC files get decoded in your browser via a WebAssembly build of the libheif decoder. The HEIC is converted to JPEG internally, then re-encoded to whatever output format you pick.
▶Does my image upload anywhere?
No. Decoding and re-encoding both happen in your browser via the canvas API plus an in-browser HEIC decoder. Disconnect from the internet after the page loads and the tool still works.
▶Why is AVIF sometimes greyed out?
AVIF encoding requires browser-native support. Chrome, Edge, and Opera support it. Firefox can decode AVIF but only recent versions can encode it. Safari support is partial. If your browser can't encode AVIF, the tool tells you so you don't waste time.
▶What's the difference between PNG and JPG?
PNG is lossless: every pixel is preserved exactly. Best for screenshots, logos, anything with crisp edges or transparency. JPG is lossy: it throws away detail you wouldn't notice to make files smaller. Best for photos.
▶Should I use WebP or AVIF for the web?
WebP if you want broad support today: every modern browser back several years opens it. AVIF if you need the smallest possible file and don't care about Safari versions older than 16.4 / IE / very old Android.
▶What happens with animated GIFs?
Only the first frame gets converted. For animated GIF to MP4/WebM conversion, you'll need a video tool. To keep an animation in GIF form, just leave the file as-is.
▶What's the file size limit?
50 MB per image. Browsers will sometimes hit memory limits before that with very high-megapixel raws. If a large file fails to load, compress it first.