Scotsman has time, very long time to produce picture (7)
I believe the answer is:
montage
'picture' is the definition.
(I have seen 'Composite picture' mean 'montage' so perhaps 'picture' could also mean 'montage')
'scotsman has time very long time' is the wordplay.
'scotsman' becomes 'mon'.
'has' says to put letters next to each other.
'time' becomes 't'.
'very long time' becomes 'age' (I've seen this before).
'mon'+'t'+'age'='MONTAGE'
'to produce' acts as a link.
(Other definitions for montage that I've seen before include "Film sequence" , "Picture created from a number of images" , "Composite picture" , "Picture comprising disparate elements" , "Artwork - not a gem (anag)" .)