Returning half the silver seized and the pictures (6)
I believe the answer is:
images
'the pictures' is the definition.
('image' can be a synonym of 'picture')
'returning half the silver seized' is the wordplay.
'returning' is a reversal indicator.
'half' becomes 'semi' (I've seen this before).
'the silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'seized' is an insertion indicator.
'semi' back-to-front is 'imes'.
'imes' enclosing 'ag' is 'IMAGES'.
'and' is the link.
(Other definitions for images that I've seen before include "Visual counterparts in lens or mirror" , "Photos or likenesses" , "Likenesses or effigies" , "Pictures, representations" , "Pictures; metaphors" .)