I don't think the 922 has the feature to allow you to access pictures from a USB device like the 722 does.
The 922 has DLNA support, so it can display images, they just have to be hosted on a separate machine on the network.
They probably could do the USB support, I just don't see it as an advertised feature of the 922 anywhere. I hooked a CF card to my 922 with a USB adapter but I couldn't find any way to access it.