Sweet picture, perhaps added by discrete software module (5,4)
I believe the answer is:
apple tart
'sweet' is the definition.
(I've seen this before)
'picture perhaps added by discrete software module' is the wordplay.
I cannot really see how this works, but
'software' could be 'app' (I've seen this before) and 'app' is found within the answer.
'picture perhaps' could be 'art' (picture is a kind of art) and 'art' is present in the answer.
The remaining letters 'let' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for apple tart that I've seen before include "Dessert" , "Pastry" , "Sweet" .)