XF 2.0 Is there a relatively simple way to allow a BBCode for quoting a user's avatar?

[dissentience]

Hello, I'm looking for a way to display a user's avatar in a post using BBCode and their user number, ie:

[avatar=3343]

Does anyone know if this is possible, and if so, how I might go about it? I've searched but can't seem to find anything. Thank you!