Two photos from a Nokia 8.3 5G end in .heif. Read the first few bytes and both call themselves heic, the same label an iPhone puts on its .heic files. Going the other way, a small test image named spring_1440x960.heic leads with mif1, the plain HEIF label. The ending on a file tells you less than the file does.
On 27 September 2026 we read the insides of 69 public files with the HEIF reader our converters use: six photos and samples people have posted (two iPhones, two Nokia phones, two test images) and the 63 files of Nokia’s HEIF conformance set, which was made to exercise the format’s features. Then we converted every one of them to JPG with our HEIF to JPG tool, once in Chrome 153 and once in Safari’s engine (WebKit 26.6), both on a Mac.
One container, several names
HEIF is the container: a box format that holds one or more pictures, their thumbnails, depth maps and metadata. It says nothing about how each picture is compressed. HEIC is what you get when the pictures inside are compressed with HEVC, which is what phones write. The first box of every file lists brands, short labels that say which rules it follows, and the first of them is the main one.
| File | Ending | Main brand, then the others | Picture | Stored as |
|---|---|---|---|---|
| Nokia 8.3 5G photo | .heif | heic; mif1 | 4608×3456, 8-bit | 63 tiles of 512×512 |
| Nokia 8.3 5G HDR shot | .heif | heic; mif1, miaf, MiHB | 4608×3456, 8-bit | 63 tiles |
| iPhone 13 Pro Max | .heic | heic; mif1, MiHE, MiPr, miaf, MiHB | 4032×3024, 8-bit | 48 tiles, plus an HDR gain map |
| iPhone 11 Pro Max | .HEIC | heic; mif1 | 2566×3313, 8-bit | 42 tiles |
| Sample posted as .heif | .heif | heic; mif1 | 640×426, 8-bit | one picture |
| 1440×960 test image | .heic | mif1; heic | 1440×960, 8-bit | one picture, plus a thumbnail |
Both Nokia files are HEIC in everything but the name. Phones store a big photo as a grid of small tiles that are put back together when it opens, which is why a 16-megapixel photo is 63 pictures inside. Nothing about that changes with the ending.
The Nokia “HDR” shot is not HDR in the file-format sense either. Its picture is 8-bit and carries no colour description at all, so the high dynamic range was merged into ordinary pixels by the phone before saving. The iPhone 13 Pro Max file is the one with an extra layer for HDR screens, a gain map stored beside the main picture.
Some cameras save HEIF with a .hif ending, often at 10 bits per colour. We had no public camera file to test, so what follows about 10-bit and HDR comes from the conformance set and from how our converter is built, not from a camera.
What the format allows, from the conformance set
Nokia’s set is where the variety shows. Of its 63 files, 52 open as still images with a picture list; the other 11 are image sequences, stored like a short video track instead, with msf1 as the main brand.
| Feature | Files | What it means for you |
|---|---|---|
| Image sequence (msf1, a video-style track) | 11 | A burst or animation; converters that expect one still picture may refuse it |
| More than one picture in the file | 30 | Up to 11 in one file; a converter takes the one marked as main |
| Picture built from a grid of tiles | 2 | How phones store full-size photos |
| See-through areas (alpha) | 2 | Kept when converted to PNG, filled with white in JPG |
| 10 bits per colour | 1 | Reduced to 8 bits by most converters, ours included |
| Pictures compressed with H.264 instead of HEVC (avci) | 1 | Still HEIF, but not HEIC |
| A later rule set (mif2) as the main brand | 2 | Both failed in our own decoder; Safari opened them |
| A thumbnail stored beside the picture | 6 | Not carried into the converted copy |
Which of the 69 files opened
Safari’s engine opened and converted all 69, sequences and the H.264 file included, because Safari hands HEIF to the operating system’s own decoder. Other browsers have none, so there our converter uses its own, and in Chrome it converted 54.
| Files | Safari’s engine | Chrome (our own decoder) |
|---|---|---|
| Phone photos and posted samples (6) | 6 | 6 |
| Conformance, still images (52) | 52 | 48 |
| Conformance, image sequences (11) | 11 | 0 |
| All 69 | 69 | 54 |
The four still images our decoder missed are the two newer mif2 files, the H.264 file and one two-picture file (C021 in the set). None of the phone photos was affected. If a HEIF file won’t open in Chrome, Edge or Firefox, opening the same page in Safari is the quickest way round it; on a Windows PC, the camera maker’s own software is the other.
10-bit and HDR
The one 10-bit file in the set converted in both browsers. A JPG holds 8 bits per colour, so the extra precision is gone in the copy. Our converter does not tone-map HDR pictures stored with a PQ or HLG curve, the way some cameras save their HDR modes: those come out flat or washed out, and the camera maker’s software is the better tool for them.
Converting keeps nothing else from the file: no location, no date, no camera details, no thumbnail, no gain map. Our HEIC to JPG measurements list what an iPhone file carries and what its JPG copy loses, and HEIF to PNG keeps every pixel of the main picture when you need to edit it again.