This is the sort of pointless photo I'd take to test that my gear was working properly. I won't be so quick to delete these in future!
In that case, i'm a Billionaire!!
I kind of liked the "99 Cent II Diptychon", which was the most expensive a few years ago. It kind of tells a story, and gives a nice colourful insight into the 'dreary' lives of people with less cash.
The "Untitled #96" I'd never heard of until now, and it's not such a bad photo now that i've seen it, but not the best one in the world imho.
But the expensive art world isn't about what looks good. It's all about advertising and speculating. You wouldn't pay $5mil for a nice photo by a nobody, you pay $5mil for a half-decent photo by a well-known name. And you only pay $5mil for it if you think you can get it back (and then some) in future.
(Do some reading by the critics of Saatchi for example, allegedly he finds nobodies, buys all their work for cheap, in doing so gives them a 'name', then sells their stuff a bit later for a very nice profit).
Reminds me of when the Australian government bought "Blue Poles: Number 11, 1952" for $2mil, and everyone complained, now it's worth well over $40mil, could be $100mil at auction. $2mil doesn't seem so expensive now, does it?