ManicMobile

If you are wondering what the file extension ITHMB is,  it is actually a picture file format utilized by the Apple IPOD.   So it is actually a photo format simliar to GIF, and JPG.

This format is usually used for thumbnails which is why the file extension ITHMB  (short for THUMBnail, and of course, the usual letter “I” at the start which is heavily associated with Apple such ash (iphone, ipod, itunes..etc).
Technically the ITHMB files are 16-bit uncompressed raw picture.  If you are wondering why uncompressed,  i think it is because having to uncompress photos on-the-fly needs a greater processing power and will drain your batteries faster.