The page on the left is from a 1978 book called Nate the Great Goes Undercover, by Marc Simont. The poster of Emily the Strange on the right is from 1991.
From "You Thought We Wouldn't Notice," a blog that points out art swipes:
If you've ever walked into a Hot Topic, you are somewhat familiar with Emily, but on the off-chance that you haven't, you can get aquainted with her at her big fat website. She was designed in 1991, according to creator Rob Reger, as an image for use on skateboarding merchandise. Since then, she has morphed into a kind of goth pop icon. At first she was just a mouthpiece for typical Hot Topic tee slogans ("I WANT YOU to go away," "Problem Child," etc. etc.) but since has moved to full-fledged characterdom, with her own comic book series and a film slated for 2010.
Google searching for any information on this rip has yielded a tiny handful of bemused observers (this one offering the most analysis), but as far as I can tell no real action has been taken. I doubt that neither Marjorie Weinman Sharmat nor Marc Simont (the author and illustrator of the Nate the Great books, respectively) is aware of the appropriation of their character. I plan to send a letter to each c/o of their publishers as soon as possible. I really do think something should be done. This stolen character has already made millions for its "creator" and the fact that she will have her own film is clear testament of how big she's gotten.
I wonder if Reger is giving Simont a percentage of the sales from Emily merchandise?