One is forced to strip anything after the .jpg or else one will get
"The URL you specified is invalid." when using "Link off-site:
Enter the URL of the location containing the avatar image you wish to
link to."

This bug is still present in the 3.1 demo.

The files are exactly the same.

$ wget http://www.gravatar.com/avatar/47edd1ee4d973c50bbe7991bb063d09d.jpg?s=80 -O A
$ wget http://www.gravatar.com/avatar/47edd1ee4d973c50bbe7991bb063d09d.jpg -O B
$ sum A B
25586 4 A
25586 4 B

Please ignore that they are from Gravatar. That is beside the point.

"Upload from a URL:
Enter the URL of the location containing the image. The image will be copied to this site." is also affected.