Picture tropical river banks (5)
I believe the answer is:
photo
'picture' is the definition.
(a photograph)
'tropical river banks' is the wordplay.
'tropical' becomes 'hot' (similar in meaning).
'river' becomes 'Po' (Italian river).
'banks' indicates putting letters inside (bank can mean to surround or border).
'hot' inserted into 'po' is 'PHOTO'.
(Other definitions for photo that I've seen before include "Camera picture" , "Snap (abbrev.)" , "Still" , "Picture (abbr)" , "Pic (abbr)" .)