When using $my->getAvatar() the default size is SOCIAL_AVATAR_MEDIUM and it returns an image with dimensions 64px X 64px.

When a user does not have an avatar uploaded, the new feature Text Based Avatar returns 180px X 180px.

https://monosnap.com/file/H3dNfixGREahJirjcTnPt8r5S3Naoo

I have not tried changing the parameter in getAvatar() method but I would guess it would not return a bigger text based avatar bigger than 180px x 180px.

Thanks,

Jackson