That was a guess on my part, but I didn’t find anything else to fit the description. There also seem to be groups dedicated to modding the original hardware for things like direct capture to digital (to bypass the tapes), or at least there were at some point. Anyway, pretty cool stuff.
This is true, and the grayscale images could have a different colored tint when displayed on a Game Boy Color using the palette swapping feature. The white background version found elsewhere in this thread is the closest to what one would expect if we were talking about something printed with the stock Game Boy Printer.
TLDR: Awwwwkshully…