Picture latter half of a trip to Santiago? (5)
I believe the answer is:
image
'picture' is the definition.
('image' can be a synonym of 'picture')
'latter half of a trip to santiago?' is the wordplay.
'latter half of' indicates taking half.
'a trip to santiago?' becomes 'pilgrimage'.
'pilgrimage' with half the letters taken is 'IMAGE'.
(Other definitions for image that I've seen before include "Copy" , "Reflection" , "Mental picture; idol" , "Iconic representation" , "Likeness; statue" .)