Photos disappeared
AApprox how many photos can be stored on the ipad? Where are instructions on storing and saving photos?
iPad 2, iOS 7.1, Screen blacks out
FIrst of all it depends on how much space you have on your iPad and since nobody here knows the answer to that, nobody can tell you how many photos you can store on your iPad. You can store as many as you have free space available.
Here is the iPad user guide for iOS 7 which your profile states that you are running.
https://manuals.info.apple.com/en_US/ipad_ios7_user_guide.pdf