Anyone know of an App that will allow me to connect my camera's USB cable to the Nexus (via an OTG cable) and be able to download/review/edit pictures?
Steve
you likely do NOT need a separate app if your camera is compatible. { But you can also use NMI and MTP mode ! }
set the Nexus 7 in USB camera mode
settings > storage > 3 periods at top right (menu) > USB computer connection > Camera (PTP) mode selected > exitplug the camera cable into the OTG and plug the entire assembly into the microUSB with the Camera ON.
If compatible, your pictures will be available ...
Plenty of links on the web - here is an example
http://www.hyperborea.org/journal/2012/10/nexus7-otg/