HEIC (HEIF) Format Explained — The Default iPhone Photo Format
HEIC explained: HEVC in a HEIF container (ISO/IEC 23008-12), file structure, iPhone use, 2026 browser and Windows support, and what JPG conversion loses.
HEIF (High Efficiency Image File Format) is an image container specification created by MPEG and defined in ISO/IEC 23008-12 (MPEG-H Part 12). The final draft was completed in 2015, and ISO's first edition was published in 2017. A HEIF file holding images compressed with HEVC (H.265) is commonly called HEIC, and the .heic files saved by iPhones fall into this category.
Structure
HEIF uses the ISO base media file format (ISOBMFF) structure, the same family as MP4 video. So a single file can contain several elements, such as:
- A primary image and thumbnails
- Multiple images, such as bursts and Live Photos
- Depth information from Portrait mode, alpha images for transparency
- EXIF and XMP metadata, and non-destructive edits such as rotation and cropping
Large images are also often split into multiple tiles that are compressed separately, so the decoder has to stitch the tiles back together.
iPhone and HEIC
Apple introduced HEIF/HEVC capture in iOS 11 (2017), and according to Apple Support, iPhone 7 and later models can shoot in this format. In Settings > Camera > Formats, choosing "Most Compatible" shoots JPEG, while "High Efficiency" shoots HEIC. If the receiving device doesn't support HEIF, photos may be converted to JPEG when shared via AirDrop, Messages or Mail.
Support (as of 2026-09-23)
| Environment | Support |
|---|---|
| Safari 17 or later (macOS, iOS) | Can display on web pages |
| Chrome · Edge · Firefox | Cannot display on web pages |
| macOS · iOS | Built-in support |
| Windows 10/11 | Requires the HEIF Image Extensions from the Microsoft Store (the HEVC Video Extensions may also be needed, depending on the setup) |
According to Can I use, browsers that can display HEIC account for only about 15% of users worldwide. Complex HEVC patent licensing is cited as the reason browser adoption hasn't grown, and on the web, royalty-free AVIF has taken over that role.
File signature and HEIC vs. AVIF
HEIF-family files have an ftyp box at the start, and the brand name that follows identifies the type. iPhone photos usually use the heic brand, extended profiles such as 10-bit use heix, and generic HEIF images use mif1. This marker reveals a HEIC file even if its extension has been changed to .jpg.
| Item | HEIC | AVIF |
|---|---|---|
| Container | HEIF (ISOBMFF) | HEIF (ISOBMFF) |
| Compression codec | HEVC (H.265) | AV1 |
| Codec licensing | Patent license required | Royalty-free |
| Browsers | Safari 17 or later | All major browsers |
| Android | Decoding from 8.0 | Decoding and encoding mandatory from 14 |
| Main use | iPhone and iPad cameras | Web images |
Strengths and limitations
- Smaller than JPG at the same quality, and can hold 10-bit color and HDR.
- Can gather photo-related extras in a single file.
- Poor compatibility with web upload forms and Windows programs means conversion is often needed before submitting or sharing.
Things to watch when converting
- It's normal for the file to get larger as a JPG. JPG needs more bytes to keep the same quality.
- Depth information, multiple images and HDR brightness information don't carry over to JPG.
- Simply renaming the extension to
.jpgleaves the content as HEIC, so upload forms will reject it. - The HEIC to JPG converter uses a decoder running inside the browser when the browser can't open HEIC directly, and never sends your photos to a server. Settings and usage are covered in detail in the HEIC guide.