Post office accepts stolen picture (5)
I believe the answer is:
photo
'picture' is the definition.
(a photograph)
'post office accepts stolen' is the wordplay.
'post office' becomes 'po' (abbreviation).
'accepts' is an insertion indicator.
'stolen' becomes 'hot' (stolen goods are 'hot').
'po' enclosing 'hot' is 'PHOTO'.
(Other definitions for photo that I've seen before include "Snap, exposure, in short" , "Camera picture" , "In brief, a snapshot" , "Snap - shot" , "Snap, picture" .)