Picture setter's senility (5)
I believe the answer is:
image
'picture' is the definition.
('image' can be a synonym of 'picture')
'setter's senility' is the wordplay.
'setter's' becomes 'im' (I've seen this in other clues).
'senility' becomes 'age' (I've seen this in other clues).
'im'+'age'='IMAGE'
(Other definitions for image that I've seen before include "personality" , "Likeness or mental picture" , "sculpture" , "Representation, picture" , "Visible impression" .)