Here's the pictures:
I assume each character is made of a 2x2 box, where each piece in the box can be either filled or empty.
Adjacent boxes that are filled can either be separate or connected. This would allow for 43 separate characters (I think, correct me if I'm wrong)
I agree with what someone said about the (only top right filled) and (only bottom left filled) characters being a start and end character, as they appear in the same places and nowhere else on both images.
My attention span is really short though, I'll probably get distracted in a few minutes