Image resizing on the fly in asp.net

For simplicity lets say that I have a web page that needs to display thumbnails of images. The images locations are stored in a database(the images are stored on Amazon S3). Is it possible to have my web server scale down the large image before it is delivered to the client? This way I don’t have to store thumbnails of every image and the client can download a smaller file.

Convert special chars to HTML entities, without changing tags and parameters

I’m using FreeTextBox editor to get some HTML created by users.
The problem with this is this editor is not converting special chars in HTML entities at exception of “<>”. I cannot use theHTML = Server.HtmlEncode(theHTML), because it converts all the HTML including tags and parameters, and I don’t want to create an unfinishable list of theHTML.Replace lines.