Oddly enough, both of these films are based on works of art. "Isle of the Dead" is based on a series of paintings by creepy Symbolist Swiss Painter Arnold Bocklin (1827-1901). These paintings are really beautiful and worth checking out. The "Isle" of the film really captures this mood..
The second film "Bedlam" is not as good, but still enjoyable. Karloff plays a true creepy perv in this one. I liked the lead Female character played by Anna Lee. She starts out as a Bitch, and sorta remains a Bitch, even though she becomes the "hero" of the film. And she falls in love with a hot Quaker.
"Bedlam" was based on Hogarth's "A Rake's Progress". It is the final panel where the "Rake" ends up at Bedlam (Bethlem Royal Hospital), for all of his bad behavior. Once upon a time in another life I visited Bethlem when I lived in England. I was writing a paper on an Artist who did some time there. They actually have a little museum where you can buy souvenirs. I bought a Bedlam coffee mug. Of course the place is very civilized now. Time to take some more medicine and watch Gossip Girl..