With the LibPurple chat_add_users callback, how do I get a display image from a PurpleConvChatBuddy?

In the LibPurple chat_add_users callback, you get a list of PurpleConvChatBuddy object's describing all the chat users. What is the best way to get the buddy icon / or user info photo for each of the users?

I can't find any nice way to connect a PurpleConvChatBuddy object to a buddy icon, the best I can come up with is to request the userinfo and then fig开发者_高级运维ure out the 'photo' entry in the returned values. This does not seem to be the best way to handle it in a generic way.