JFIF stands for JPEG Interchange Format. Thus, the JFIF version can be found in JPG or JPEG files only. It is a standard to define JPEG image files. It contains information that would otherwise be missing from the original JPEG Part 1 image format standard.
JFIF was developed by C-Cube Microsystems to not only store JPEG data, but to make these files more accessible across programs, systems and applications that could not or hardly support it before.
There have been different JFIF Versions over the years:
In JFIF Version 1.02, the possibility to store compressed thumbnail images was introduced.