Question, painting for example duck, size of paper (6)
I believe the answer is:
quarto
'size of paper' is the definition.
(I've seen this before)
'question painting for example duck' is the wordplay.
'question' becomes 'qu' (abbreviation).
'painting for example' becomes 'art' (painting is a kind of art).
'duck' becomes 'o' (resembles zero - 'duck' in cricket).
'qu'+'art'+'o'='QUARTO'
(Other definitions for quarto that I've seen before include "Book size resulting in folding one sheet four times" , "Ten-by-eight inch paper" , "Twice-folded paper size" , "Book page size" , "Publishing term, four leaves are formed from one sheet" .)