Picture of one wise man (5)
I believe the answer is:
image
'picture' is the definition.
('image' can be a synonym of 'picture')
'one wise man' is the wordplay.
'one' becomes 'i' (Roman numeral).
'wise man' becomes 'mage' (I've seen this before).
'i'+'mage'='IMAGE'
'of' is the link.
(Other definitions for image that I've seen before include "Photo or likeness" , "Iconic representation" , "Simulacrum" , "Visual or mental representation" , "Purplish pigment; pool" .)