Pictures — one million — taking long time (6)
I believe the answer is:
images
'pictures' is the definition.
(I know this)
'one million taking long time' is the wordplay.
'one million' becomes 'im' (resembles am, a million).
'taking' means one lot of letters go next to another.
'long time' becomes 'ages' (I've seen this in another clue).
'im'+'ages'='IMAGES'
(Other definitions for images that I've seen before include "Representations or reflections" , "Reflections in a mirror" , "Pictures, representations" , "Pictures; metaphors" , "These doubles could be spitting" .)