Why a HEIC photo does not open everywhere
HEIC is a photo file that uses the HEVC video codec inside a container called HEIF. Apple made it the default for iPhone cameras with iOS 11, and Apple's support page says iPhone 7 and later can capture in it. It stores a photo in less space than JPG, which is the reason Apple chose it.
The trouble is that HEVC is a video codec with licensing costs, and few programs include it. caniuse lists Safari 17 as the first browser version that shows HEIC and no support in Chrome, Edge or Firefox. In Chrome we confirmed it directly: asking the browser to open a HEIC file fails, which is why this page carries its own decoder.
Windows needs two add-ons from the Microsoft Store. Microsoft's support page names the HEIF Image Extensions, which are free, and the HEVC Video Extensions, which cost money, and says you need both even if you only look at photos. Many upload forms and web editors have no such add-on, so they reject the file.
What the JPG keeps and what it drops
- The picture and its colours. iPhone photos are tagged Display P3, a wider range than the sRGB that most screens and websites assume. The converter turns the colours into sRGB so they look right, and writes no colour profile.
- Not the metadata. The date taken, the camera and the GPS position are not copied. The Metadata switch cannot change that for HEIC, because the converter can copy EXIF only from JPG, PNG and WebP originals. We looked inside a converted file and found no EXIF and no colour profile.
- Not the extras. The HEIC we examined held 48 picture tiles, a 320 by 240 thumbnail and an extra greyscale picture of 768 by 576 pixels. Only the main picture is converted. A Live Photo is a still plus a short video, and this page converts the still file you give it: it cannot include the video.
- 8 bits per colour. HEIF can store more than 8 bits, but JPG stores 8. Our sample iPhone photo was 8 bit already.
The photo is turned the right way up, so it does not matter which way the phone was held. A HEIC that was cut short, for example by a transfer that stopped early, is refused with a message that says so. Without that check, a test file cut at 40 percent gave a picture with a large green block where the missing tiles should be.
Will the JPG be bigger?
Often a little, sometimes not. We converted a 12 megapixel iPhone X photo, 4032 by 3024 pixels. The HEIC was 2.7 MB, and the JPG at quality 90 was also 2.7 MB. Apple's own export of the same photo at quality 90 was 4.7 MB, so the encoder matters as much as the format.
What you control is the quality slider. At 90 most photos look like the original. Lower numbers give smaller files with visible blocks in smooth skies from about 75 down. If the list shows a JPG getting much bigger than the HEIC, lower the quality a notch, or keep the HEIC for your own library and convert only the copies you send out.
Avoiding the problem at the source
Apple lets you choose at the camera. In Settings, Camera, Formats, the option Most Compatible makes new photos JPG, and High Efficiency makes them HEIC. Existing photos keep the format they were taken in.
Apple's support page also says AirDrop, Messages and email may convert photos to JPG for a receiver that cannot read HEIC, and that importing by cable to a PC may convert them, unless you choose Keep Originals in the Photos settings. When a photo arrives as HEIC anyway, this page turns it into a JPG on your computer, with nothing uploaded.