http://www.roleplayerguild.com/posts/2783016
Okay her magic revolves around paint and pictures so she'd be a decent artist. That's still no reason why she'd have to draw a specific painting of Van Gogh. It could just as easily be said that "it was impressively detailed for a picture drawn in the dirt, appearing almost like a painting in quality". It would get the same idea across without unnecessarily dragging in a random historical piece from another world.