Appropriate images when sharing link to Gittip homepage/profile

I was telling some people about Gittip at a Coffee & Hack meetup, and a guy tried to share the site on Facebook. He mentioned that no image showed up for the homepage, which he thought was pretty important:
https://www.evernote.com/shard/s27/sh/6c774ba7-ceea-4153-a838-0cb394ca7bdd/353465d5f5f53abf9696121d594668b3

I also noticed that when sharing a profile, the only option is to share the profile pic:
https://www.evernote.com/shard/s27/sh/847b1975-b4d1-4a86-92ae-14691b73dee3/5a8cfd088aa8ef3c5435df6c667f4c8c

Might be nice to be able to choose the gittip logo or the profile pic, depending on what the sharer is most interested in communicating (themselves or the service) :)

This is a good beginner task for a non-python dev like me, so I'll take it

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