I've been spending money like crazy trying to get a decent photo viewer sorted out as I have thousands of 5000 pixel pics.
Photo Manager Pro is a decent app that lets you import pics at any res you want. The downside is it is wireless only syncing.
I also tried out file manager type apps - to my surprise, Goodreader seems to be better at rendering images than Apple's own photo app or PM Pro.
For now, I think that is the route I am going to take.