"What is this movie?" from Movie Punks

[Mofo Rising]

Movie Punks is a pretty funny webcomic about two punks who watch movies.

Anyway, currently on the front page is this message:

Can You Name This Movie?
I'm desperately seeking the name of a horror movie. Here's what I know: it was from the late 1970's (77-79), and it centers around a large house or building. It has a painting whose eyes move. There is also a scene with a shower: a snake or something like that moves underneath the mat at the bottom of the tub/shower while two (or maybe one) person is standing in it. If you have any ideas at all or even a wild guess, please e-mail me. I'd really appreciate it.

Any ideas?

[The Burgomaster]

The movie ARNOLD (1973), which is sort of a horror/comedy has a large house and a painting with moving eyes.  I'm not sure about the snakes, though . . .