What is HEIC, and why won’t anything open it?
If you have ever AirDropped a photo to a Windows PC, uploaded an iPhone picture to a form, or emailed one to someone on Android and heard "I can’t open this" - you have met HEIC.
The short version
HEIC (High Efficiency Image Container) is the photo format iPhones have used by default since iOS 11 in 2017. It stores pictures compressed with HEVC, the same technology behind modern video. HEIF can use less storage than JPEG at comparable visual quality. The size difference depends on the photo and capture settings, not a fixed one-half ratio.
Why Apple chose it
Apple did not invent HEIC - the format (HEIF) was standardized by MPEG in 2015. But Apple made it famous by making it the iPhone default. Photos, Live Photos, and bursts all save as .heic files unless you change the setting.
Why everything else struggles
Windows, most websites, and many apps predate or simply never licensed the HEVC technology inside HEIC. Windows 10 and 11 open HEIC in the Photos app only once Microsoft’s codec add-ons are in place - and iPhone shots need two of them. Most upload forms simply reject the file. That is not your photo being broken - it is the world catching up slowly.
Support is spreading, with conditions. Android has decoded HEIC at the system level since Android 9 in 2018 - but whether a specific app on a specific phone opens one still varies. On Windows, the Photos app asks for HEIF Image Extensions and HEVC Video Extensions from the Microsoft Store before it will display an iPhone .heic - some PCs ship with them, others need extensions, whose availability and price can vary. Upload forms remain the real holdout: they usually accept only JPG or PNG, which is where converting wins.
The fix
Two options. On the iPhone itself, Settings > Camera > Formats > Most Compatible makes the camera save plain JPGs going forward (JPG files can take more space than HEIC ones). For photos you already have, convert them - the HEIC to JPG converter on this site does it on your device, so the photos never get uploaded anywhere.