Related to my previous post on dynamic images, a long way back I wrote a two-part article for the now deceased (paid) website ASPToday. It was about a HttpHandler implementation that would generate a thumbnail image from an existing image. The handler was accompanied by a server control that would allow you to specify the original image as the source. The thumbnail is then created on-the-fly during run-time automatically. Since ASPToday is no longer online, I have posted the article “Developing a custom ASP.NET Web control for thumbnails” in one piece under my blog downloads. There’s source code to go with it as well. It’s an old article as I finished writing it in November 2003. Still a good read I hope (and in English).
Also, when you start generating your thumbnail images in an http handler using the new ASP.NET version for dynamic images (or my simpler implementation for that matter), give Matt’s article “Creating great thumbnails in ASP.NET” a read. You’ll find it worthwhile.