Unless the web page has an identifiable extension like .php, .asp, .aspx, .jsp, etc, then I doubt anyone can tell. Once the code get's sent back to the client, it is HTML regardless. There may be some comments in the html that would tell you though.
Hi, Randall, the image is on my local disk (C drive) with an extention .jpeg Can I e-mail you the image? I think an experience person may be able to tell right away what language was used to generate that image.