It is annoying to change between multiple subfolders, especially if there are a lot of subfolders. You have to doubleclick on the back folder icon ('..'), then scroll down to search for the folder (even it is the next to your last selected folder) and doubleclick it. The ability to view folders in a treeview would simplify this a lot, you could then change the current folder with one click or even drag and drop images to another folder to copy/move. Especially if you store your pictures in subfolders like "2008-01-01 New years eve party; 2008-01-02 birthday; 2008-01-03 trip to..." You can see a good example in GQview (set to treeview) or ACDSee for Windows.