title: c# save System.Drawing.Graphics to file
body: <p>I have a System.Drawing.Graphics took from a picturebox.</p>
  
  <p>basically I draw some lines over a background image stored into the picturebox
  now I wish save a png that contains the background image and everything is drawn over there...</p>
  
  <p>is there a way to do this?
  thanks in advance</p>