Picture of a mother displayed by designer (7)
I believe the answer is:
diorama
'picture' is the definition.
(diorama is a kind of picture)
'a mother displayed by designer' is the wordplay.
'mother' becomes 'ma' (ma is a kind of mother).
'displayed by' is a charade indicator (letters next to each other).
'designer' becomes 'dior' (dior is a designer brand).
'a'+'ma'='ama'
'ama' put after 'dior' is 'DIORAMA'.
'of' acts as a link.
(Other definitions for diorama that I've seen before include "Scene with models" , "A little set" , "Representation of scene" , "AM radio? (anag)" , "Miniature setting" .)