You must ask the AG admins if you can, and get a written proof. Very unlikely unless you can give a good reason why you want to use the pics.
Read the Terms and Conditions:
We take protection of copyrights, both our own and others, very seriously. We therefore employ multiple measures to prevent copyright infringement over this Site and to promptly end any infringement that might occur. If you believe that the Site contains elements that infringe your copyrights in your work, please contact us immediately.
In other words, it is illegal to copy the armatars without permission and sue for commercial use.
I read this too:
The Site is to be used solely for your non-commercial, non-exclusive, non-assignable, non-transferable and limited personal use and for no other purposes. You must not alter, delete or conceal any copyright or other notices contained on the Site, including notices on any Material you download, transmit, display, print or reproduce from the Site.
I guess Facebook pics count as limited personal use. Ask the admins (Not the mods), and hope for an answer.