At least one male comic book artist (Greg Land) is notorious for tracing photographic images from porn in his comics. He'll also plagiarize any non-porn art that isn't nailed down. I feel pretty sure he is not the only one doing this.
I stopped reading Ultimate Fantastic Four years ago when he took over because the tracing was so obvious I could no longer concentrate on the story. The book didn't last long because it was trash, but I was enjoying it until then. Hate that guy.
Holy sh*t, I had no idea O_o Disgusting :[
It's weird how the woman on the left looks like she was drawn using the reference of an actual female athlete, and the one on the right looks much less realistic, like someone's strange idea of how a woman should look.