Photograph first icon in personal computer (3)
I believe the answer is:
pic
'photograph' is the definition.
(I've seen this in other clues)
'first icon in personal computer' is the wordplay.
'first' indicates taking the first letters.
'in' means one lot of letters goes inside another.
'personal computer' becomes 'pc' ('PC' can be a synonym of 'personal computer').
The initial letter of 'icon' is 'i'.
'i' inserted into 'pc' is 'PIC'.
(Other definitions for pic that I've seen before include "film" , "Photograph (colloq.)" , "Photo (colloq.)" , "Snapshot" , "Image (abbr)" .)