Still a wizard on the Mac? (5)
I believe the answer is:
image
'still' is the definition.
(as in a photographic still)
'a wizard on the mac?' is the wordplay.
'a wizard' becomes 'mage'.
'on' is a charade indicator (letters next to each other).
'the mac?' becomes 'i' (I can't justify this - if you can you should believe this answer much more).
'mage' put after 'i' is 'IMAGE'.
(Other definitions for image that I've seen before include "Simile, metaphor" , "Visible impression" , "Idol; simile" , "Representation, picture" , "Purplish pigment; pool" .)