Picture that is printed on exterior of magazine (5)
I believe the answer is:
image
'picture' is the definition.
('image' can be a synonym of 'picture')
'that is printed on exterior of magazine' is the wordplay.
'that is' becomes 'ie' ('i.e.' can be a synonym of 'that is').
'printed on exterior of' indicates putting letters inside (I've seen this in other clues).
'magazine' becomes 'mag' (abbreviation for magazine).
'ie' going around 'mag' is 'IMAGE'.
(Other definitions for image that I've seen before include "Visible impression" , "Iconic representation" , "Simulacrum" , "Simile, metaphor" , "Idol; simile" .)