I've been trying to change the album cover for the one photo album I have for a few weeks. I keep trying to make this picture be the album cover. Each time I try, I use the Edit Pictures button, select the appropriate "This is the album cover" radio button, and save. Then, ALL my pictures become moderated for a while (presumably until a mod hits a magic button) and then reverts back to the old sideways picture of me as a guy.
I'm not quite sure why the change wouldn't go through after the pictures had been re-approved, but I've gone in and made that photo you linked to the album cover.