PBF file preview? is is in pair with coresponding video MKV/MP4 etc

[Adamaji74]

Is it possible to add a thumbnail preview to .PBF - Portable Bookmarks File?

Some sample files:
https://mega.nz/file/K81kABDS#VlbY9ezSnzGbxwRNghcbKmzn-lfn0a7_dNToLgOG3l4

PBF file is created as external (text file like structure) for example with DAUM Pot Player [http://www.videohelp.com/software/PotPlayer].
For video/audio files.

EDIT:
Thumb file is last long string in line. Image in JPEG format starts at position 89. char (indexed from 1) with "FFD8FFE00..." and ends with "FFD9".

I tested this with an online tool:
https://tomeko.net/online_tools/hex_to_file.php

[Xanashi]

I'll look into it. It does seem doable.
Do you know if there is an official specification for the pbf file format?