Small picture contains etching, somewhat reduced (5)
I believe the answer is:
inset
'small picture' is the definition.
(I've seen this before)
'contains etching somewhat reduced' is the wordplay.
'somewhat reduced' says the answer is hidden in the clue.
'INSET' is hidden within 'contains etching'.
(Other definitions for inset that I've seen before include "Small map within another" , "Put (one thing) into (another)" , "Tines (anag.)" , "Part of magazine" , "day for teachers" .)