Saving an image to a folder

Hello,
       I am creating a paint application on web similar to the one showed on http://canvaspaint.org/
      I am trying to save images drawn on canvas element to a folder on local server (i.e., in a folder in my project) using VB. Can i get any sample code snippet for me to go about this.
 I tried it with using Application.StartuPath. But, it shows an error "startuppath is not a member of system.web.httpapplicationstate". Also, I am not sure about how to save canvas image to a png/jpeg in .net.

Any help on this will help me a lot to proceed!!
Thanks
Sowjanya

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