Not for iMessage.
Messages is obviously iChat under the hood.
This allows you to change your Buddy Pic in the or for the Buddy lists.
However iMessages relies on the fact you are connecting to Contacts you already know and who know you.
This will mean your Contacts List (formerly the Address Book) will have pics associated with most people that connect to you and Message pulls that pic.
On their iPhone, iPad or Mac their version does the same for you.
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
iMac 2.5Ghz 5i 2011 (Mountain Lion 10.8.2)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad
"Limit the Logs to the Bits above Binary Images." No, Seriously