Well, ASP generates the HTML code as it's a server side script. Now what you could do is knock out the the url of image form that thumbnail image and open it in enlarge,pop up, new window etc... But you said your JS is not working.....so it would be nice if you could atleast post the code, cause it could be some problem with JS if you have already made.

And if you havn't made it yet, use HTML DOM, style properties&methods(using JS only) and you will get it.

If you didn't understood what I said you may post here.