Picture book about illustrated little men escaping their frames

[Lyndsay]

It was a book without words, involving little illustrated men escaping their photo frames with ladders and tunnels and interacting in eachother's paintings and illustrations and having adventures before returning to their frames. Probably from the 70's-80's, as I read it in my grandmother's house.

[Rainbowheart]

This sounds super familiar to me. I wonder if I read it as a little kid.

I know you said you think the book was from the '70s or '80s, but what year did you first come across it?