I started this blog with theme Twenty Twelve but did not like the fact that the menus were above the header image. So I have changed it to Twenty Ten which has the menus under the header image. Twenty Ten also allows random display of a selection of header images, and I’ve set it up to display among six images, all photos I have taken (except the one of me underwater). My only irritation so far with Twenty Ten is that it does not allow larger header images like Twenty Twelve, but I can live with that. Remains to see whether I find other limitations.
Mountains and rivers
Explorations by Colin Mathers
Mountains and rivers 
Interesting. You are now using the same theme that I am using and having tried a number in the free range I haven’t found one I like better.
I meant to say I like the way it scrolls through the header picture. I might look at how that is done and do it also.
Took me a few moments to figure it out. Simply select, crop and install each of the header images you want to use one by one. There is an option below all the header images to allow random selection on the blog pages, tick that and it works. I had actually tried to set this up in Twenty Twelve but it seemed only to be possible by purchasing a customization option. So that was one reason I changed, but the main one was to get the header above the menus. Incidentally, did you recognize the view in one of the header images?