HEIC (High Efficiency Image Container) holds HEIF images compressed with the HEVC codec. On iPhone, it is the format behind the camera's High Efficiency setting.
When a marketplace does not accept HEIC, converting to JPG before upload avoids the error; the HEIC to JPG converter does it in the browser.
What HEIC is and why phones use it
HEIC is a newer way of storing a photo than JPEG. It compresses the picture more efficiently, so a photo of the same visible quality takes about half the storage. That is why iPhones save photos in it by default, and many Android phones offer it as a setting.
A HEIC file can also hold more than a single picture: a sequence of pictures, or a photo together with its depth map. On the phone this is useful. For a product listing only the single still image matters.
Where HEIC causes trouble
The format is well supported inside one phone maker's devices and unevenly outside them. Many web browsers cannot display it, some image editors need an extra component to open it, and a number of marketplaces and shop systems reject it at upload.
The usual sign is an upload that fails without a clear reason, or a file that arrives on a computer with an ending the software does not know. Phones often convert photos silently when they are shared by mail or message, which is why the problem appears with some ways of transferring files and not with others.
Two ways around it
The first is to convert. Turning a HEIC photo into a JPEG takes a moment and loses no visible quality when the JPEG quality is set high. The original can stay on the phone as the archive copy.
The second is to stop the phone from using HEIC. The camera settings offer a choice between the efficient format and a more compatible one; the compatible setting saves JPEG from the start, at the price of larger files.
HEIC and other image formats
- Image file format
- The image file format is the general term: the way a picture is stored in a file. HEIC is one such format, alongside JPEG, PNG and WebP, and each marketplace lists the ones it accepts.
- WebP
- WebP is another efficient format, made for the web. Browsers display it widely, which cannot be said of HEIC, but phone cameras do not save photos in it.
- Image compression
- Image compression is how a file is made smaller. HEIC uses a newer method than JPEG, which is where its smaller files come from.
- sRGB colour space
- sRGB is a colour space, not a format. Phone photos are often saved in a wider colour space, so the conversion to JPEG is a good moment to convert the colours to sRGB as well.
A checklist for HEIC photos
- The sales channel's list of accepted formats was checked before a HEIC file was uploaded.
- The conversion to JPEG used a high quality setting, and the result was compared with the original at full size.
- The converted file is in sRGB, so that the colours do not shift in a browser.
- The image dimensions are unchanged; some ways of sharing a photo shrink it while converting it.
- The HEIC original is kept as the master copy, and edits start from it, not from an already compressed JPEG.