Here's a page from an old Captain Marvel give-away coloring book published in 1941.
What is nice about the book is that the art seems to be an original effort and not just enlarged panels cut from a comic book. Humorously, it is also full of unabashed hucksterism urging children to purchase copies of Whiz Comics in order to make sure they color the characters properly.
Now that is some Golden Age greatness. It's amusing how the artist has Captain Marvel saving the helpless ingenue from being impaled by firmly gripping the Rhino's huge, strategically-placed horn with one hand while cupping a giant handful of cheek in the other.
You can use a photo-manipulation program or print it out and color it in the real world.
FYI: Here is what an actual Rhino looks like.
Tags: Captain Marvel Coloring Book SOTI