Religious image I study (4)
I believe the answer is:
icon
'religious image' is the definition.
(I've seen this in another clue)
'i study' is the wordplay.
'study' becomes 'con' (con can mean to study).
'i'+'con'='ICON'
(Other definitions for icon that I've seen before include "Religious image or computer symbol" , "Computer graphic symbol" , "Holy painting" , "Adored person" , "Computer-screen symbol" .)