Long story captured by profile picture (4)
I believe the answer is:
epic
'long story' is the definition.
(eg an epic poem)
'captured by profile picture' is the wordplay.
'captured by' indicates a hidden word.
'EPIC' is hidden in the letters of 'profile picture'.
(Other definitions for epic that I've seen before include "Film or book on a grand scale" , "Long adventure story" , "Long classic film" , "Long poem, book, film" , "Large in scale" .)