Thumbnail URL in activities

[Resseguie]

I'm working on a custom activities list, similar to the standard
gadget, but styled and arranged slightly different.

I want to include a profile pic but the thumbnail URL field doesn't
seem to be populated when you request activities. I can make a
separate request using the supplied user ID, but that seems
inefficient. Am I just missing something? Do I need to specifically
request that URL as a parameter perhaps like when fetching people?

[Bob Aman]

I would recommend doing a batch request. You can add more then one
request before sending it out.

-Bob