CTF games come in two styles (attack and defense i.e. PvP, and jeopardy i.e. PvE), and within the jeopardy class there are many categories, one or which can be

CTF games come in two styles (attack and defense i.e. PvP, and jeopardy i.e. PvE), and within the jeopardy class there are many categories, one or which can be steganography, file formats, and related challenges. (Source: I run a CTF, have written over 100 challenges, and the JPEG padding trick was one of them years ago)