Post Image plugin?

Thats sort of what i was looking for, But on my site i’ve got this title block with a border and was wanting to change the background of that to a random image. Maybe based on what is said in the post or who posts it or just completely random. Major thing that it must do is be faint so not to make text hard to read. And Crop to the size of the block, which should be the same all the time unless title is really long.