One drink swallowed by Miss West in picture (7)
I believe the answer is:
imagine
'picture' is the definition.
(picture can mean to visualise or imagine)
'one drink swallowed by miss west' is the wordplay.
'one' becomes 'i' (Roman numeral).
'drink' becomes 'gin' (gin is an alcoholic drink).
'swallowed by' means one lot of letters goes inside another.
'miss west' becomes 'mae' (I've seen this in another clue).
'gin' put into 'mae' is 'magine'.
'i'+'magine'='IMAGINE'
'in' acts as a link.
(Other definitions for imagine that I've seen before include "John Lennon classic (just think of it!)" , "Reckon" , "Lennon song - dream" , "Suspect" , "1971 John Lennon song" .)