Hi,
you can implement that feature by using image map in asp.net.
first you've to set particular portion of image as click link so when user mouseover that portion the javascript function raises that feature.
This is just idea only .Try your self with your own code
Here 'm providing link for learn imagemap
http://www.codeproject.com/KB/user-controls/imagemap.aspx
Google maps are also based on image map only.
so can achieve your requirement by using Imagemap.
All the Best