Picture with gangster out in the open (6)
I believe the answer is:
fresco
'picture' is the definition.
(fresco is a kind of picture)
'gangster out in the open' is the wordplay.
'gangster' becomes 'al' (Al Capone).
'out' indicates named letters should be taken away.
'in the open' becomes 'alfresco' (I've seen this before).
'alfresco' with 'al' taken out is 'FRESCO'.
'with' acts as a link.
(Other definitions for fresco that I've seen before include "Painting done in wet plaster" , "Mode of wall painting" , "Method of painting on walls" , "Painting style" , "Forces (anag) - wall painting" .)