Picture frame contains silver leaf (4)
I believe the answer is:
page
'leaf' is the definition.
(page is a kind of leaf)
'picture frame contains silver' is the wordplay.
'picture frame' becomes 'pe' (I've seen this in other clues).
'contains' means one lot of letters goes inside another.
'silver' becomes 'ag' (Ag is the chemical symbol for silver).
'pe' placed around 'ag' is 'PAGE'.
(Other definitions for page that I've seen before include "Messenger" , "contact" , "Leaf - boy attendant" , "Call out the name of" , "Leaf; call over PA system" .)