Capricious press agencies reject pics with great enthusiasm (9)
I believe the answer is:
eagerness
'great enthusiasm' is the definition.
'capricious press agencies reject pics' is the wordplay.
'capricious' indicates anagramming the letters.
'reject' indicates named letters should be taken away.
'press'+'agencies'='pressagencies'
'pressagencies' with 'pics' taken out is 'resagenes'.
'resagenes' with letters rearranged gives 'EAGERNESS'.
'with' is the link.
(Other definitions for eagerness that I've seen before include "Keen interest" , "Avidity" , "'Keenness, avidness (9)'" , "Keenness, enthusiasm" , "Sense rage (anag.)" .)