Pig and Hart', recreated by painter (7)
I believe the answer is:
hogarth
'painter' is the definition.
(I know that Hogarth is a old master)
'pig and hart' recreated' is the wordplay.
'pig' becomes 'hog' (synonyms).
'and' means one lot of letters go next to another.
'recreated' is an anagram indicator.
'hart' anagrammed gives 'arth'.
'hog'+'arth'='HOGARTH'
'by' is the link.
(Other definitions for hogarth that I've seen before include "English painter and engraver, 1697-1764" , "William -, eighteenth century English engraver" , "William --, painter and satirist" , "Satirical 18th century painter" , "William --, English artist and engraver" .)