GIF Image

Format	GIF Image
Short name	GIF
Category	media
Platforms	Windows, macOS, Linux, iOS, Android, QNX
Crush support	Supported `(ImageParser)`
Status	Reviewed
Last reviewed	2026-10-04

Forensic relevance

Palette-based image format supporting animation, used in messaging apps, browser caches, and social media. Limited to 256 colors per frame — genuine photos in GIF format are rare and worth scrutinizing. GIF89a adds animation frames, comment extensions (free-text metadata), plain text extensions, and application extensions. The file terminates with a trailer byte (0x3B) — any data appended after the trailer is forensically significant. Steganography is possible via LSB encoding in the global color palette, palette reordering, or data hidden in comment/application extension blocks. Animated GIFs can hide different content in individual frames. A C2PA (Content Credentials) manifest, when present, is carried in a dedicated Application Extension block (identifier 'C2PA_GIF') and can record generating/editing software and an IPTC Digital Source Type — a direct AI-generation/-editing signal.

Signatures

Offset	Hex	ASCII (non-printable as .)	Description
offset 0 (0x0)	47 49 46 38 37 61	GIF87a	GIF87a header — static images only
offset 0 (0x0)	47 49 46 38 39 61	GIF89a	GIF89a header — animation, comments, and extensions supported

Known extensions

.gif

References

GIF89a format spec https://www.w3.org/Graphics/GIF/spec-gif89a.txt
ForensicsWiki — GIF https://forensics.wiki/gif/
GIF steganography from first principles https://dtm.uk/gif-steganography/
C2PA Technical Specification (Content Credentials) https://spec.c2pa.org/specifications/specifications/2.4/specs/C2PA_Specification.html

Cite this entry

Crush Format Reference, “GIF Image”. https://kalink0.github.io/crush-forensics/formats/gif/ — source: crush/data/build_formats_db.py at commit 640a2a9928f4e36a976b89901512a8dce824d093, built 2026-10-21 06:46:19 UTC.

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