Hi Rodney, not sure if this is helpful or not but here goes:

I'm testing running dotnetnuke on Amazon ec2 at the moment. It just so happens that having installed everything Amazon sent me an email saying my instance was running on outdated hardware and that I should stop/start my instance to get moved over to new hardware.

Once I'd completed this step I also decided to upgrade to 6.2.3 and setup a new Amazon elastic IP address (which I'd been messing about with) to have my site running on a proper domain.

Once I'd done all this I noticed the profile images had disappeared. On investigation I noticed that if I loaded the site from its amazon public dns the images loaded fine - but if I loaded using the proper url they didn't show. This pointed me to the domain alias settings location in Admin Menu > Site settings > advanced settings > site aliases.

In here I noticed that my default alias was set to an outdated Amazon Public DNS address that I'd been playing around with while running 6.2.2

When I updated the default alias to the new url or the new elastic IP address or the public Amazon DNS everything worked fine.

(Whether my change above was the fix or not I'm not entirely sure but perhaps it's of use to you)

Having said that I notice that on the standard skin, when logged in, the icons for messages and notifications often don't load until the page is reloaded a couple of times - I don't know if anyone else had this problem?