Query string makes problem in page loading

Mar 11 2011 4:16 AM

Hi.
I created a page with address "~/default.aspx" and an image in it with url "~/Data/rabbit.jpg" and a link. after clicking the link, a query string is added to url. I mean href attribute for link is: href="default.aspx/?param=value".
after page is reloaded, image is not shown. What's the problem? What is tilde before urls?
Thanks