Gravatar has avators for all its users, which could potentially include everyone online. File types icons are much more limited. The rank of the first set is i

Gravatar has avators for all its users, which could potentially include everyone online. File types icons are much more limited. The rank of the first set is in the multi-hundred millions, while the later can be ~50. There is enough room in my /var/www/pub/images for 50 x ~40kB. (my entire disk storage, 300GB, can only hold avatars for 63M people.)