Allow use of Gravatar

[bitinn]

my avatar will serve as a living proof of such need... alternatively, handle PNG thumbnail generation a bit more nicely :)

For reference: https://secure.gravatar.com/avatar/9a8104ac432b50b9f01f0d75be493699?s=200

[dorentus]

本来就支持 gravatar 的啊…

前段时间我每次想改头像都是直接换 email 的，生效最快…

[bitinn]

哦原来可以取消头像……