Arrived with artist one means to produce portrait (6)
I believe the answer is:
camera
'one means to produce portrait' is the definition.
I can't tell whether this definition defines the answer.
'arrived with artist' is the wordplay.
'arrived' becomes 'came' (coming is a kind of arriving).
'with' means one lot of letters go next to another.
'artist' becomes 'ra' (Royal Academician, member of Royal Academy of Arts).
'came'+'ra'='CAMERA'
Can you help me to learn more?
(Other definitions for camera that I've seen before include "TV studio item" , "Brownie, for example" , "Item of film and TV equipment" , "media producer" , "Nullify" .)