Son has sexy photograph (4)
'photograph' is the definition.
(shot is a kind of photograph)
'son has sexy' is the wordplay.
'son' becomes 's'.
'has' says to put letters next to each other.
'sexy' becomes 'hot' (similar in meaning).
(Other definitions for shot that I've seen before include "Wounded", "glass of spirits", "Short drink; attempt", "Exhausted", "Fired from a weapon".)