No difficulty over large picture holder (5)
I believe the answer is:
easel
'picture holder' is the definition.
(I've seen this in another clue)
'no difficulty over large' is the wordplay.
'no difficulty' becomes 'ease' (ease is the opposite of difficulty).
'over' is a charade indicator (letters next to each other) (in a down clue, some letters go over others).
'large' becomes 'L' (eg in clothes sizes).
'ease'+'l'='EASEL'
(Other definitions for easel that I've seen before include "Artist's stand for painting" , "Painting support" , "dead-headed plant" , "The rest of artists" , "Artist's equipment" .)