Painting of couple by river in boat (7)
I believe the answer is:
artwork
'painting' is the definition.
(I've seen this before)
'couple by river in boat' is the wordplay.
'couple' becomes 'two' (two people or things).
'by' says to put letters next to each other.
'river' becomes 'r' (abbreviation for river).
'in' means one lot of letters goes inside another.
'boat' becomes 'ark' (ark is a kind of boat).
'two' put after 'r' is 'rtwo'.
'rtwo' going inside 'ark' is 'ARTWORK'.
'of' acts as a link.
(Other definitions for artwork that I've seen before include "Illustrations in book" , "Illustrations and designs for printing" , "Illustrations prepared for a publication" , "Illustrative material in publication" , "Painting" .)