Title says it all...
Please see Jon Galloway's post on this topic:
Also, there is a control already available : http://www.carknee.com/archive/2007/03/13/asp-net-gravatar-control.aspx
Please work on your question posting skills! Seriously, that is a very abrasive aprroach you have taken that is not going to help you solve your problem.
- start with an introduction
- describe the problem in words
- post code snippets in moderation
- thank us in advance
good luck
EDIT 1: by golly, you were trying to help people out. Still, even if just a motion, use the above approach. Spewing code is useless.
EDIT 2: You've added an introduction, and with that, I'll undo my down vote and even add an up vote as a consultation prize. "Good on you" for being responsive to the negative criticism. Many a SOpedian would have just walked off in a huff.
I can't see where the email address is being converted to lowercase as per "How the URL is constructed"
See: http://gravatarnet.codeplex.com/ for my .NET implementation of the Gravatar API.
see [link text][1]
[1]: http://madskristensen.net/post/Gravatares-new-features-and-ASPNET.aspx and find out how to solve the problem