Lifted picture from big book (5)
I believe the answer is:
folio
'big book' is the definition.
(I've seen this in another clue)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for folio that I've seen before include "Folded sheet - or book made from such" , "Sheet of paper folded to make two book leaves" , "Sheet folded to form two leaves in book - page number" , "Four pages" , "Book size" .)