Speak unkindly of a picture (4)
I believe the answer is:
snap
This clue could be a double definition.
'speak unkindly' is the first definition.
'snap' can be an answer for 'speak' (snapping is a kind of speaking). I am not sure about the 'unkindly' bit.
'a picture' is the second definition.
(I've seen this before)
'of' acts as a link.
Can you help me to learn more?
(Other definitions for snap that I've seen before include "Break suddenly and abruptly" , "Cut" , "Break like simple card game" , "A walk in the park < to shoot" , "Simple card-game" .)