[ape4]

But there are lots of BMP versions - wiki says "Many different versions of some of these structures can appear in the file, due to the long evolution of this file format."

[Retr0id]

Exactly. It is easy to write a BMP reader, but if you want to read any BMP file that you might find in the wild then you're going to have a fun time.

[duskwuff]

There's even some very niche extensions to BMP which allow it to be used as a container for PNG or JPEG data.

https://learn.microsoft.com/en-us/windows/win32/gdi/jpeg-and...