Convert an image to another format
What this tool does
Pick the format you want out, and the image is decoded and re-encoded in your browser tab. Transparency, colour and orientation are handled for you, and the file never reaches a server.
This browser cannot convert images locally. It needs Web Workers with OffscreenCanvas support, and we will not fall back to converting on the main thread because that would freeze the page. Please try a current version of Chrome, Edge, Firefox or Safari.
That is a HEIC or HEIF file, the format iPhones and many cameras shoot by default. This browser cannot decode it natively, so a decoder is fetched from this site to read it — still on your device, still never uploaded.
How this works
The image is decoded, redrawn and re-encoded inside a Web Worker in this browser tab. Nothing is uploaded, and there is no file-size limit imposed by a server because there is no server.
- The format list is built from what your browser can actually encode, tested at load time. A format the browser cannot write is not offered, rather than silently producing something else.
- Converting to JPEG flattens transparency onto white, because JPEG has no alpha channel. The result panel says so when it happens.
- HEIC and HEIF files from an iPhone work: Safari reads them directly, and other browsers fetch a small decoder that runs on your device.
- A batch converts every image to the same format and returns them as one ZIP.
- Re-encoding an already-optimised image can add a few bytes. The readout shows what actually happened rather than promising a saving.
Frequently asked questions
Which format should I choose?
WebP is the best default: small files, wide support and transparency. Choose JPEG for maximum compatibility — it cannot store transparency, so it is flattened onto white — and PNG when you need lossless detail.
Why can't I convert to AVIF here?
Because browsers cannot write AVIF from a canvas: asking for it returns a PNG instead, silently. Rather than hand you a file in the wrong format, the format list only offers what this browser proved it can really write, and AVIF files can still be used as input.
What happens to transparency when I convert to JPEG?
JPEG cannot store an alpha channel, so transparent areas are flattened onto a solid background. The result panel says so when it happens, and WebP or PNG keeps the transparency intact.
Can I convert several images at once?
Yes, as a batch: every image is converted in the same worker, and the converted files download together in one ZIP.
Can I convert the HEIC photos from my iPhone?
Yes. Safari reads them directly; other browsers fetch a small decoder, which runs on your device like everything else here. Nothing is uploaded either way.