AFCP

AFCP (AXS File Concatenation Protocol) is a metadata format for image files. Its main uses are embedding IPTC-IIM data, and thumbnail images. It's not clear what AXS refers to.

It is designed to be used as a "trailer" that can be appended to a number of different file formats. It could potentially be used in other ways, and even has TIFF tag 34152 assigned to it. But it is not a self-contained format (it contains pointers relative to the beginning of the file), so such use would be problematic.

Identification
In most cases, the signature "" or "" appears beginning 12 bytes from the end of the file.

Specifications

 * AXS File Concatenation Protocol
 * Another copy, from archive.org

Software

 * ExifTool
 * Metadata++

Sample files

 * AFCP.jpg
 * 

Links

 * Information from ExifTool