Why do photos not appear in ipad Photos/LIbrary (but I found them in recents!)

Took Photos with Ipad. 5 days later I could not find them! After hours of searching (and serious panic), I found them in "recents", but NOT in Library. I hope this is helpful to people, and I hope someone gives me a gold star or whatever, but it would also be very useful if someone explained this:

Isn't Library the superset, the sum total of all pics stored locally on the ipad? Why on earth would recent photos NOT be in Library "folder" ?

THanks,

-TPC