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Reference Formats

FLIF

An experimental royalty-free lossless raster format aiming to beat PNG and lossless WebP compression, using MANIAC entropy coding and progressive interlacing so a partial file still renders a usable preview.

Extension

.flif

Full name

Free Lossless Image Format

Introduced

October 2015

Vendor

Jon Sneyers and Pieter Wuille

What is inside the container

FLIF supports arbitrary bit depth, alpha transparency, and animation, and its progressive design means any sufficiently large chunk of the file can be decoded as a lossy preview of the full image. It has no standardized metadata block equivalent to EXIF/IPTC/XMP, and development stopped after its creator merged the ideas into a successor project that ultimately became part of JPEG XL, leaving FLIF itself frozen and effectively unmaintained.

How to open it

Command line the reference FLIF encoder/decoder tools from the original project
GIMP limited support only through a community plugin, not built in
Mainstream OS/browsers/creative tools no native support in Windows, macOS, major browsers, Photoshop, or Lightroom
JPEG XL tooling successor-format encoders (libjxl) are the practical migration path rather than continued FLIF tooling

For archives

Avoid FLIF for DAM ingestion or long-term storage: the format is effectively discontinued, having been folded into the effort that became JPEG XL, and has never had broad application or OS support. Any legacy FLIF assets in a collection should be converted to PNG or JPEG XL promptly rather than kept as the format of record.

Jon Sneyers released FLIF in October 2015, working with Pieter Wuille, aiming to outperform PNG, lossless WebP, and lossless JPEG 2000 on compression ratio while adding a distinctive progressive-decoding trick: because of its MANIAC entropy coding, a partial download of a FLIF file could still be decoded as a recognizable, if blurry, preview of the whole image, well beyond simple interlacing.

FLIF never reached broad adoption, and its own creator moved on: Sneyers combined FLIF’s ideas with lossy compression techniques to create the Free Universal Image Format, which was subsequently merged into JPEG XL. That leaves FLIF a dead end for DAM purposes — there is no camera, browser, or major creative tool that produces or consumes it natively, and no ongoing development to fix that. If a FLIF file surfaces in a collection (most likely from an experimental workflow around 2015-2018), the right move is a one-time conversion to a live format rather than treating FLIF as an archival target.

Frequently asked

Should a DAM accept FLIF as an ongoing ingestion format?

No. Avoid FLIF for ingestion or long-term storage; the format is effectively discontinued, having been folded into the effort that became JPEG XL, and never had broad application or OS support.

What should happen to legacy FLIF assets already in a collection?

Convert them to PNG or JPEG XL promptly rather than keeping FLIF as the format of record, since active tooling and support have moved on.

Does FLIF support structured metadata like EXIF or XMP?

No. It has no standardized metadata block equivalent to EXIF, IPTC, or XMP.

What was FLIF's technical goal?

To beat PNG and lossless WebP compression using MANIAC entropy coding, with a progressive interlacing design so a partial file still renders a usable preview.

Is FLIF supported in mainstream operating systems or creative tools?

No. There is no native support in Windows, macOS, major browsers, Photoshop, or Lightroom; only the reference encoder/decoder tools and a limited community GIMP plugin exist.

What happened to FLIF's development?

It stopped after its creator merged the format's ideas into a successor project that ultimately became part of JPEG XL, leaving FLIF itself frozen and unmaintained.

What is the practical migration path for FLIF assets?

JPEG XL tooling, specifically libjxl-based encoders, since JPEG XL absorbed FLIF's underlying ideas and is the actively maintained successor format.

Does FLIF support animation and transparency?

Yes. FLIF supports arbitrary bit depth, alpha transparency, and animation, but that capability is moot for DAM purposes given the format's discontinued status.

Sources