Pictured being one thousand years old (6)
I believe the answer is:
imaged
'pictured' is the definition.
('image' can be a synonym of 'picture')
'one thousand years old' is the wordplay.
'one' becomes 'i' (Roman numeral).
'thousand' becomes 'm' (Roman numeral for a thousand).
'years old' becomes 'aged' (I can't explain this - if you can you should give a lot more credence to this answer).
'i'+'m'+'aged'='IMAGED'
'being' acts as a link.
Can you help me to learn more?
(Other definitions for imaged that I've seen before include "shown in picture" , "Copied" , "Fancied" , "Formed a picture of" .)