Why did you need to map .jpg to ASP ISAPI filter? Why not just call someimage.asp and set the mime type and use BinaryWrite?
BTW, great conversion technique. Certainly something to do nowadays too, if you can get them to load an image or click a link. I wonder, do average people load images in emails or click the links "if this email does not render correctly"?
I feared some mail programs might filter out non-standard file extensions loading from an img tag. Probably paranoid but it was so easy to run .jpg through the ISAPI filter of a single site that it seemed prudent to do that.
BTW, great conversion technique. Certainly something to do nowadays too, if you can get them to load an image or click a link. I wonder, do average people load images in emails or click the links "if this email does not render correctly"?