Why iPhones save in HEIC (and why it's a problem)
In 2017 Apple switched the default iPhone camera format from JPEG to HEIC, short for High Efficiency Image Container. It saves photos at roughly half the file size of JPEG for the same visual quality — great for your phone's storage, less great for everywhere else. Gmail attachments, Slack messages, older Windows machines, most job-application portals, and a surprising number of CMSs still reject it outright.
The fix is simple: convert to JPEG. The question is just where. Most desktop tools send your photos to a server, which for personal or sensitive images you probably don't want. This page does the whole thing in your browser with WebAssembly. The file never leaves your computer.
How the quality setting works
JPG quality is a number from 0 to 100. At 85 — the default here — photos are visually indistinguishable from the original and still compress well. Drop it to 70 if you need a smaller file for email. Push it to 95 if the photo is going to print.
When to convert vs. keep HEIC
- Convert to JPG if you're uploading, emailing, or sharing with non-Apple users.
- Keep HEIC if the photo is staying in your Apple ecosystem — Photos app, AirDrop between iPhones, iCloud.
- Convert and archive both if you care about the original file but need a shareable copy now.
Frequently asked
Does this upload my photos anywhere?
No. The HEIC decoder runs as WebAssembly inside your browser tab. Your images are decoded and re-encoded on your own device's CPU. You can turn off Wi-Fi after the page loads and it still works.
Why is the first conversion slow?
The HEIC decoder is a ~3 MB WebAssembly module. Your browser downloads it once the first time you convert an image, then caches it. Every conversion after that is fast.
Does it keep EXIF data (camera info, location, date)?
Most of it is preserved in the JPG. GPS coordinates and camera make/model typically survive. If you want to strip those for privacy, run the result through the compressor afterwards.
My file says .HEIC in caps — will it still work?
Yes. The file extension is case-insensitive, and the tool also reads the file's actual bytes to confirm it's HEIC.
Why are some HEIC files failing to convert?
A small number of HEIC variants use 10-bit colour or unusual codecs that the in-browser decoder doesn't handle. These are rare — usually from third-party camera apps rather than the native iPhone camera.