I'd say to get, if you have the money, the 32 Gb model + a 32 or 64 Gb Micro SD. With incomming Kit Kat Micro SD restrictions, you won't be fully able to use all of the SD power, so a lot of internal memory is a good, if you install lots of apps...
If you are shorter on money or won't use it much for apps, mostly media, get a 16 + 64 Gb combo.
About image viewing, the Sony Album app is pretty gorgeous and really smooth, and an incoming update will make that even better. It's not the very best to organize everything (a file manager would be the best for that), but the UI is gorgeous and clean. The screen is really gorgeous and colors don't change even at extreme angles.