Load an image from a url into a PictureBox
The PictureBox.Load(string url) method "sets the ImageLocation to the specified URL and displays the image indicated."
yourPictureBox.ImageLocation = "http://www.gravatar.com/avatar/6810d91caff032b202c50701dd3af745?d=identicon&r=PG"
Try this:
var request = WebRequest.Create("http://www.gravatar.com/avatar/6810d91caff032b202c50701dd3af745?d=identicon&r=PG");
using (var response = request.GetResponse())
using (var stream = response.GetResponseStream())
{
pictureBox1.Image = Bitmap.FromStream(stream);
}