This writer's old as visualised (6)
I believe the answer is:
imaged
'visualised' is the definition.
('image' can be a synonym of 'visualize')
'this writer's old' is the wordplay.
'this writer's' becomes 'im' (the person writing the crossword clues).
'old' becomes 'aged' ('aged' can be similar in meaning to 'old').
'im'+'aged'='IMAGED'
'as' acts as a link.
(Other definitions for imaged that I've seen before include "Formed a picture of" , "Copied" , "Fancied" , "shown in picture" .)