Picture that is about mother on alcohol (7)
I believe the answer is:
imagine
'picture' is the definition.
(thesaurus)
'that is about mother on alcohol' is the wordplay.
'that is' becomes 'ie' ('i.e.' can be a synonym of 'that is').
'about' indicates putting letters inside.
'mother' becomes 'ma' (ma is a kind of mother).
'on' means one lot of letters go next to another.
'alcohol' becomes 'gin' (gin is a kind of alcohol).
'ma'+'gin'='magin'
'ie' enclosing 'magin' is 'IMAGINE'.
(Other definitions for imagine that I've seen before include "Suppose; think up" , "Conceive in the mind" , "John Lennon hit" , "Form a mental picture" , "Enigma, I? (anag)" .)