Convert HEIC to WebP

Because most of your visitors would see nothing. Chrome and Firefox cannot decode HEIC — Google and Mozilla both declined to license the patent-encumbered HEVC codec it wraps — so a HEIC on a web page is a broken image for the large majority of the web. Safari is the exception. WebP is supported by every current browser and has been since Safari 14 in 2020.

AVIF produces smaller files than WebP at matching quality and is the better format on the merits. The practical arguments for WebP are that it has a few more years of universal support behind it, and that it encodes in milliseconds where AVIF can take seconds per image. For a handful of photographs either is fine; for a few hundred, the encoding time stops being an abstraction.

Typically somewhere between the same size and about 40% larger, which is a far better outcome than JPEG's roughly double. Both formats descend from modern video codecs and compress photographs in broadly similar ways, so relatively little is given up in the move — you are mostly paying for compatibility rather than for quality.

Probably, and for anything you are publishing that is a feature rather than a problem. Photos taken on a phone carry GPS coordinates accurate to a few metres, and posting them to a listing or a public gallery discloses exactly where the picture was taken — frequently someone's home. Check the original HEIC if you need that data preserved, and check the output if you need it gone.

Usually, yes. A 12-megapixel photo is around 1.6 MB as HEIC and around 2.1 MB as WebP — about 31% larger. Because WebP is lossless the result depends entirely on the image content — flat colour and text compress far better than photographic detail.

Slightly. Re-encoding one lossy format as another means a second round of compression, which can soften fine detail. In practice the loss is hard to see at high quality settings, and WebP's newer codec often preserves detail better than the HEIC original did. Keep quality at 80 or above and the difference will not be visible at normal viewing size.

Yes. Both HEIC and WebP support an alpha channel, so transparent and semi-transparent pixels carry across unchanged — a logo with a cut-out background stays cut out, and soft drop shadows keep their gradient rather than picking up a white halo. Because WebP can compress lossily, a very hard edge against transparency may pick up slight softness at high compression; keep quality at 85 or above for cut-out graphics.

Only the first frame is converted. Every conversion here decodes one frame onto a canvas and re-encodes it, so the result is always a still image — that applies to WebP as much as to any other target. To shrink an animation while keeping the motion, a video file (MP4 or WebM) is usually around a tenth of the size of the equivalent HEIC, and needs an encoder we do not ship yet.

HEIC uses the patent-encumbered HEVC codec, which Google and Mozilla declined to license, so Chrome and Firefox cannot display it at all. Windows can, but only after installing a paid HEVC extension from the Microsoft Store. Converting to WebP sidesteps the whole problem — and you can stop the issue at the source by setting your iPhone to Settings → Camera → Formats → Most Compatible, which saves JPEGs instead.