Retaining the silver, returned half the pictures (6)
I believe the answer is:
images
'the pictures' is the definition.
('image' can be a synonym of 'picture')
'retaining the silver returned half' is the wordplay.
'retaining' means one lot of letters goes inside another (inserted letters are held or retained).
'the silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'returned' is a reversal indicator.
'half' becomes 'semi' (I've seen this before).
'semi' back-to-front is 'imes'.
'ag' placed inside 'imes' is 'IMAGES'.
(Other definitions for images that I've seen before include "Pictures; metaphors" , "Ageism (anag)" , "Semblances" , "Likenesses or impressions" , "'Reflections, likenesses (6)'" .)