Obsession with self-image on a shot (8)
I believe the answer is:
egomania
'obsession with self' is the definition.
(egomania is obsession with one's self)
'image on a shot' is the wordplay.
'shot' indicates an anagram.
'image'+'on'+'a'='imageona'
'imageona' with letters rearranged gives 'EGOMANIA'.
(Other definitions for egomania that I've seen before include "Obsessive self-conceit" , "Thing about me" , "not caring about others" , "Excessive pride" , "obsession with self" .)