ipad 4 camera roll not saving pictures

i have ipad 4 that was given to me last month the firmware:11.60.00 ios 10.3.3(14G60) 13.13GB capacity.

my problem is why after i shot a pictures then when i restart my ipad my picture on my camera roll has gone and why my table has no restriction setting under general settings

i read some forums they said its possile it is ipad 4 demo. my questions? what is the difference of ipad 4 demo and retail ipad 4? how to know if its demo or not? thnks