Travel document containing University student’s image (6)
I believe the answer is:
visual
'image' is the definition.
(visual image is a kind of image)
'travel document containing university student's' is the wordplay.
'travel document' becomes 'visa' (I've seen this before).
'containing' means one lot of letters goes inside another.
'university' becomes 'u' (abbreviation for university).
'student' becomes 'l' (as in L-plates for learner drivers).
'visa' enclosing 'u' is 'visua'.
'visua'+'l'='VISUAL'
(Other definitions for visual that I've seen before include "Relating to seeing" , "Of or used in seeing" , "Of the eyes or sight" , "Relating to, or using, sight" , "Of sight and seeing" .)