A computer image from Silicon Valley (4)
I believe the answer is:
icon
'a computer image' is the definition.
(I've seen this in another clue)
'from silicon valley' is the wordplay.
'from' indicates a hidden word.
'ICON' is hidden within 'silicon valley'.
(Other definitions for icon that I've seen before include "found on desktop" , "Venerated person (or thing)" , "Computer-screen symbol" , "Revered person or symbol" , "Image on computer screen representing facility" .)