Mm... I seem to have lost the wo/o at some point in my previous quote.
I didn't understand how they could actually be talking about making images and, due to that, got hung up on using na as a sentence particle to break things up. However, I just now looked at the artist site and browsed the full flow of events (including the middle image not posted here) and guess they really are talking about the image itself. *sigh* Giving that he says the image of a girl covered in blood is unsightly and that he tells her to eat an apple, putting it all together would seem to give something along those lines.
Haplo said: The thing is that マニアック is usually an enthusiast, a (sports) fan. I don't know if it's used with other meanings.
That's how I usually encounter it. It's usually in a sexual context too (like a hips "maniac" or breasts "maniac"), although that could just be because I spend too much time around h-manga. In this case I'm thinking it might mean something like "fetishy drawings."