A small photograph of savoury jelly (5)
I believe the answer is:
aspic
'savoury jelly' is the definition.
(I've seen this before)
'a small photograph' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'photograph' becomes 'pic' (I've seen this in other clues).
'a'+'s'+'pic'='ASPIC'
'of' is the link.
(Other definitions for aspic that I've seen before include "Jelly based on fish or meat stock" , "Ending of Marlowe's thriller" , "Savoury jelly used to coat eggs etc" , "Savoury jelly for meat or vegetable" , "Savoury jelly for coating meats and eggs" .)