Image MIME Reference
FLIF
Free Lossless Image Format
image/flif
VS
High Efficiency Image Container
image/heic
HEIC
A complete technical comparison of Free Lossless Image Format and High Efficiency Image Container — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
HEIC wins on browser support
Feature Support
| Feature | FLIF | HEIC |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | Yes | Yes |
| Progressive Loading | Yes | ✕ No |
| HDR Support | Yes | Yes |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | Yes | Yes |
Free Lossless Image Format
image/flif
Extension
.flif
Container
FLIF Bitstream
Compression
Lossless (MANIAC Entropy Coding)
Algorithm
MANIAC (Meta-Adaptive Near-zero Integer Arithmetic Coding)
Color Depth
1-bit to 16-bit (Per Channel), Grayscale, RGB, RGBA, CMYK
Developed by
Jon Sneyers and Pieter Wuille (Cloudinary)
Released
2015
Magic Bytes
46 4C 49 46
High Efficiency Image Container
image/heic
Extension
.heic
Container
HEIF / ISOBMFF
Compression
Lossy / Lossless
Algorithm
HEVC (H.265)
Color Depth
8-bit, 10-bit, 12-bit, 16-bit
Developed by
MPEG (Standard) / Apple (Adoption)
Released
2017
Magic Bytes
XX XX XX XX 66 74 79 70 68 65 69 63
Browser Support Comparison
| Browser | FLIF | HEIC |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ |
✓ 11+
|
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
FLIF
FLIF Strengths
- Achieves some of the highest lossless compression ratios ever developed for raster images
- Incredible progressive decoding allows an image to be highly recognizable even after only 5% of the file has been downloaded
- Supports animations and complex alpha channels losslessly
Limitations
- Officially abandoned in favor of JPEG XL
- Zero native support in web browsers or standard operating system previewers
- Encoding speed can be significantly slower than standard PNG or WebP compression
HEIC
HEIC Strengths
- Exceptional compression efficiency — stores images at roughly half the file size of JPEG with equal or better visual quality
- Natively supports modern photography features like depth maps, 16-bit color, HDR, and alpha channel transparency
- Can store image bursts, focal stacks, and animations (Live Photos) within a single file
Limitations
- Heavily encumbered by software patents, leading to very poor adoption outside the Apple ecosystem
- Not supported by standard web browsers (except Safari), requiring server-side or client-side conversion for web delivery
- Windows requires downloading a separate (often paid) extension from the Microsoft Store to view natively
When to choose which format
FLIF
Use FLIF when…
- Archival of Uncompressed Image Assets
- Bandwidth-Constrained Progressive Image Loading (Historical)
- Medical and Scientific Imaging Storage
HEIC
Use HEIC when…
- iOS / iPhone Photography
- macOS Ecosystem
- High-Quality Image Archiving