Made some improvements to this today.
There are several monsters that show noart.gif for the monster image because it is variable, so I added images for those monsters including random generators. These monsters are: one of Doctor Weirdeaux's creations, Slime Tube monster, time-spinner prank, wall of meat. I couldn't think of the correct solution for the time-spinner prank so I settled for an enjoyable solution.
Also, there are a bunch of monsters from batfellow that show blank images. I've fixed them to properly display a version of the proper criminals. These monsters are: common criminal, uncommon criminal, rare criminal, low-level mook, mid-level mook, high-level mook, time bandit, burner, former guard.
Feedback on my solutions for these images is welcome.