Is about to study religious pictures (5)
I believe the answer is:
icons
'religious pictures' is the definition.
(I've seen this before)
'is about to study' is the wordplay.
'about' means one lot of letters goes inside another.
'to study' becomes 'con' (conning is a kind of studying).
'is' enclosing 'con' is 'ICONS'.
(Other definitions for icons that I've seen before include "Celebrities" , "Screen symbols on 4 across" , "representative figures?" , "Religious or computer images" , "Sonic (anag)" .)