title: how to set an smaallest image as windowBackground keeping aspect ratio
body: <p>seeking experts attention.. I wanna set an image(which is smaller than
  device screen resulation) as background of my
  app .. I want it to fill the entire window but
  keeping the ascpect ratio of image... (if the
  image aspect ratio doesn't match with window
  aspect ratio, image will be cropped) .</p>
  
  <p>NOTE:this is possible, see Contacs+ app..they did it..No matter how small the is, it fill the window, keeps aspect ratio(doesn't stretch) and the rest of the image is cropped.
  Can anybody
  give me sollution for this</p>