Picture showing anger perhaps about cocaine (8)
I believe the answer is:
emoticon
'picture' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'anger perhaps about cocaine' is the wordplay.
'anger perhaps' becomes 'emotion' (anger is a kind of emotion).
'about' indicates putting letters inside.
'cocaine' becomes 'C' (drugs abbreviation).
'emotion' enclosing 'c' is 'EMOTICON'.
'showing' acts as a link.
Can you help me to learn more?
(Other definitions for emoticon that I've seen before include "symbol of modern communication" , "Representation of a facial expression in electronic messages" , "Graphic way of conveying feeling in e-mails" , "Wordless expression" , "state of mind symbol" .)