I was unable to get any resource ID's from with the camera gallery on Android and ended up using the press/tap touch actions to hit x,y coordiantes for a specific "picture" location.
In Ruby it would be something like:
You can use a case statement or other logic to set the x,y coordinates for the picture of your choice.
I normally, try to avoid using x,y locations and prefer to identify elements, however I'm not sure that is possible in this case. Other app implementations may have other permissions/locators to hook into.