Whenever you're composing a message, you can click the brackets with an ellipsis between them. See on the right side of this screenshot:

Clicking that will allow you to dynamically insert any person attribute you want.

If you click the "+" icon on the left, you'll be able to insert HTML code. When you're in the HTML editor, you'll see the same bracket icon again to insert any attribute. If you have an attribute that links to an image, just write some basic HTML and insert the values from that attribute where appropriate.

I personally haven't done this before, but I'm confident that this should work.