This last example (monika.chr) seems straightforward, doesn’t it? A simple PNG. Would I lie to you?
I don’t even know what that flaming circle is. Maybe an ouroboros hint or subliminal clue. That square – at first, some people thought it was a QR code but no.
It is 140 pixels on a side, black and white representing 1s and 0s and thus a binary file. One of my commentors said it needed several manipulations, inverting the grey scale, removing some pixels from the bottom row (50, I think), otherwise it looked like UTF-7 instead of -8 — so it would convert properly into Base 64 format and only then yield a text file.
Actually, one of my early pages deal with this same topic but I wanted this set to be complete for my friends at the ACA.