Writer getting sack after the end of photo shoot (4,4)
I believe the answer is:
open fire
'shoot' is the definition.
(I know that open fire is a more specific form of the action shoot)
'writer getting sack after the end of photo' is the wordplay.
I cannot really see how this works, but
'writer' could be 'pen' (something which writes) and 'pen' is found in the answer.
'sack' could be 'fire' (both can mean to dismiss from a job) and 'fire' is found in the answer.
'of' could be 'o' and 'o' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
(Other definitions for open fire that I've seen before include "army command" , "This may need log on to start" , "old-fashioned heater" , "Source of heat" , "Start attack" .)