What is HEIC, and why won’t it open everywhere?
HEIC is Apple’s name for photos stored in the HEIF container using HEVC (H.265) compression. iPhones have saved photos this way by default since iOS 11 because it takes roughly half the space of JPG at similar quality. Support outside Apple’s ecosystem is patchy, largely because of HEVC patent licensing — which is why many websites and Windows apps can’t open .heic files.
This converter sidesteps that: it uses the browser’s own decoder where available and otherwise a WebAssembly build of the open-source libheif library, all on your device. Going the other way, GIF to HEIF exports a frame as a HEIF image.
Animating iPhone photos
Burst photos and sequences shot a second or two apart make great GIFs: drop them in order, set 100–200 ms per frame for motion or 1 s for a slideshow, and keep the width around 480–720 px. If the GIF comes out large, the GIF compressor can trim it down. Got a Live Photo or video instead? Export it as a video and use Video to GIF; to go from GIF to an iPhone Live Photo, try GIF to Live Photo.