Unexpected photograph (4)
I believe the answer is:
snap
This clue is a double definition.
'unexpected' is the first definition.
(I've seen this before)
'photograph' is the second definition.
(synonyms)
(Other definitions for snap that I've seen before include "Short spell" , "you may take on holiday" , "Cut" , "Break sharply - a simple card game" , "Simple card game - gotcha!" .)