Image MIME Reference
AVIF
AV1 Image File Format
image/avif
VS
Free Lossless Image Format
image/flif
FLIF
A complete technical comparison of AV1 Image File Format and Free Lossless Image Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
AVIF wins on browser support
Feature Support
| Feature | AVIF | FLIF |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | Yes | Yes |
| Progressive Loading | ✕ No | Yes |
| HDR Support | Yes | Yes |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | Yes | Yes |
AV1 Image File Format
image/avif
Extension
.avif
Container
HEIF / ISOBMFF
Compression
AV1 Lossy / AV1 Lossless
Algorithm
AV1
Color Depth
8-bit, 10-bit, 12-bit
Developed by
Alliance for Open Media (AOMedia)
Released
2019
Magic Bytes
XX XX XX XX 66 74 79 70 61 76 69 66
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
Browser Support Comparison
| Browser | AVIF | FLIF |
|---|---|---|
|
|
✓ 85+
|
✕ |
|
|
✓ 93+
|
✕ |
|
|
✓ 16+
|
✕ |
|
|
✓ 121+
|
✕ |
|
|
✕ | ✕ |
AVIF
AVIF Strengths
- Best-in-class compression — typically 20–50% smaller than WebP at equivalent quality
- Native HDR and wide color gamut (BT.2020) support
- Supports 8, 10, and 12-bit color depth
Limitations
- Encoding is highly CPU-intensive — significantly slower than JPEG or WebP
- Requires Edge 121+ (not supported in earlier Edge versions)
- Limited support in native desktop image viewers
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
When to choose which format
AVIF
Use AVIF when…
- Next-Gen Websites
- HDR Photography
- High-Quality Web Images
FLIF
Use FLIF when…
- Archival of Uncompressed Image Assets
- Bandwidth-Constrained Progressive Image Loading (Historical)
- Medical and Scientific Imaging Storage