Picture may take a goalkeeper by surprise (8)
I believe the answer is:
snapshot
'surprise' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'picture may take a goalkeeper' is the wordplay.
'picture' becomes 'snap' (I've seen this before).
'may take' is a charade indicator (letters next to each other).
'a goalkeeper' becomes 'shot' (I can't justify this - if you can you should believe this answer much more).
'snap'+'shot'='SNAPSHOT'
'by' acts as a link.
Can you help me to learn more?
(Other definitions for snapshot that I've seen before include "Pan hosts over casual photo" , "Quickly taken photograph" , "image" , "Quick photograph" , "Informal photo" .)