cards: poor formatting for smaller avatar sizes

[lucascolley]

From www.scipy.org/teams:

Maybe the functionality to centre the smaller avatars and move the text to the bottom of the box already exists, and we just need to change something on the scipy.org size? Or maybe something needs to be changed with the card infra?

[stefanv]

Easiest may be to modify team_query.py to add a width attribute to the images. It would make the small ones a bit blurry, but at least they'd all be the same size.