Postfix header_checks using regexp and multiple lines
I'm posting this because it wasn't easy or obvious how this would be accomplished and the man page leaves it to guesswork.
Multi-line body_checks
Example 1
/<img src="cid:part.*"/
/height="430"/ REJECT
Example 2
/<img src="cid:part.*"/
/height="430" width="430" align="center" border="0">/ REDIRECT junkbox@domain.com