For iMessage for MacOS, where do the face images come from?
I don't know of a solution where you can prioritize where the contact information is pulled from, but I would imagine your default is your locally saved contact. 

I recommend you to save all of your contacts into one place, possibly create a new gmail account, and pull all of your locally saved contacts, facebook contacts, and other gmail contacts into this new account.

After that I would remove all of your other contacts from your device by going to 
Settings > Contacts > Accounts
and then removing all of the accounts.

After that I would add your new source of all of your contacts and only use one, to ensure that's where it is coming from.

Please reply to this if it is confusing.

Source: Happened to me before.