Image converter that never uploads your photos
Drop up to 100 HEIC, WebP, AVIF, PNG or JPG files, pick a format, download a ZIP. Every photo is decoded and re-encoded right here on your device.
- HEIC from iPhone
- Batch of 100 → ZIP
- JPG · PNG · WebP · AVIF · PDF · ICO
- Works offline once loaded
Drop photos on the light box
HEIC, WebP, AVIF, PNG, JPG, GIF, BMP, TIFF or SVG · up to 100 at once · converted on this device
Tip: you can also paste a copied image.
Good web quality, much smaller.
Downsizes only; SVG is drawn at this size (default 1024).
Pick a conversion
Each page opens the converter with the right output already chosen, plus notes specific to that pair of formats.
Which format should the picture end up in?
| You’re… | Convert to | Why |
|---|---|---|
| Sharing iPhone photos with Windows, Android or a web form | JPG | Opens everywhere; quality 85–92 |
| Logo, sticker or cut-out with transparency | PNG (or WebP for web) | JPG would fill the background |
| Photos for your own website | WebP or AVIF | Smallest files that every current browser shows |
| Screenshots with text | PNG | Lossless keeps letters crisp |
| Documents a form wants as one file | One photo per page, A4 or Letter | |
| Website favicon | ICO | Six sizes in one file |
How it stays on your device
When you press Convert, the page reads each file’s first bytes to identify it, whatever its name says. HEIC goes to libheif, AVIF to the browser or libavif, TIFF to the UTIF decoder. Everything else is decoded by the browser’s own engine.
The decoded pixels are drawn on an off-screen canvas, resized if you asked, and handed to an encoder: the browser for JPG, PNG and WebP, WebAssembly libavif for AVIF, pdf-lib for PDF. The result is a download link that points to memory in this tab. No request carrying your image ever leaves the page, which you can check in your browser’s network panel.
Not sure which format? Ask the advisor
Describe the image and where it’s going, including any size limit. The advisor suggests a format, a quality setting and a pixel size. Only your text is sent (to an AI model via Vercel AI Gateway), never your image.
Questions people ask
Are my images uploaded anywhere?
No. ConvertFast downloads its decoders (libheif, libavif, libwebp compiled to WebAssembly, plus the browser’s own image engine) and runs them in this tab. Your files are read from disk into memory and written back as downloads. You can load the page, turn on airplane mode, and it still converts.
How many images can I convert at once?
Up to 100 per batch. When there is more than one result you can download them all as a single ZIP file; PDF output combines them into one document instead.
Which formats are supported?
Input: HEIC/HEIF, AVIF, WebP, PNG, JPG, GIF, BMP, TIFF and SVG. Output: JPG, PNG, WebP, AVIF, PDF and ICO.
Does it work on iPhone and Android?
Yes. It runs in Safari, Chrome, Firefox and Edge on phones and computers. Large batches are faster on a computer because every image is decoded in memory.
Is it free? Is there a watermark?
Free, no watermark, no account. Your quality and size settings are remembered in this browser only; see the privacy page to clear them.
Why is my converted file bigger than the original?
Going from an efficient format (HEIC, AVIF, WebP) to an older one (JPG, PNG) usually makes files larger, because the older compression needs more data for the same picture. Lower the quality or set a longest edge to shrink it.