HOW TO: Generate Thumbnails on the Fly using ASP.NET

Generating Thumbnails on the Fly using ASP.NET! by Karl Moore (Developer.com)
Generating thumbnail images on the fly using ASP.NET and GDI+ by Karthik Giddu (WimDOWS.net)
An ASP.NET thumbnail solution by Philipos Sakellaropoulos (CodeProject.com) - Describes a set of ASP.NET tools for generation of thumbnails and thumbnail views.
Generating ASP.NET Images on the Fly by Peter Todorov (SitePoint) - Also see reader's comments for alternative solution.
Resize Images To Thumbnails in .NET by Robbe D. Morris (EggHeadCafe.com)