This feels like jumping through hoops to put a round peg in a square hole. There are dozens of image formats, but only three that are supported in web browsers. That's what web standards dictate. HEIC is an internal storage format only - it's never been intended for use outside of Apple Photos. If you export an image, it's converted to JPG. When I export from Apple Photos, HEIC is not even an option. No web browser should do things outside of web standards - the first 15 years of the web were a hell of proprietary shenanigans that we're thankful to be past (so please don't ask why Safari doesn't support HEIC - that's the last thing we should want!) So, two questions: 1) How in the world are you getting images out of your phone or Apple Photos that are still in HEIC format? How were they not auto-converted to JPG? 2) Why do you want to display a non-standard format in the browser rather than convert it first like you would with, say, a TIFF?