Avatar alt tags in Buddypress

Hello again,

I've noticed that depending on where it appears, the alt tag for Buddypress avatars is either "Avatar Image" or "Member avatar". I would love to change this! But I can't find it?! I've done a site-wide search of the code in Dreamweaver, but it can't seem to find where this happens.

Can someone point me in the right direction?

thnx!
-jennyb