php doubt

hi i am working with php on a postgres server .so i have some doubt's. my project is a student information management system on an apache web server using php and postgres as backend my doubts are 1.i wanna insert a timestamp type into db and php doesn't have such a type so i use int for timestamp.is there ne better wayz 2 do this 2.i wanna store some photographs in a db.so is it better 2 a)store the whole photograph as a large object in a db or b)to store just the file names in db and have the photographs in a dir on the server. i think b is better in terms of efficiency but i still have a doubt. which is better? 3.are ther ne session management scripts avilable ?if so plz give me the pointers.i use phplib and it causes a lot of headache. plz provide some pointers thanks in advance bye suman