Interesting how true that is! A colleague of mine is a freelance photographer next to his daily job as programmer. I myself am also interested in photography but also do plenty of things with 3D rendered artwork.
But is Photoshop not programming-related? I don't know, since web development these days does involve the use of many small icons, pictures and graphics. Almost every application will start with it's own splash-screen and plenty of sites use logo's and small pictures in their websites. And with the Copyright Police monitoring the Web very closely, these days, I think it is practical for developers of small projects to be able to at least generate their own logo's, icons and graphics.
Of course, graphic design should not be done by developers in general but by Graphics specialists. But to be honest, if you're working on a small project, it's a lot cheaper when you can just create your own images.