title: background image in smaller resolution
body: <p>I have a big background image with x1600 width. It suit perfectly in 1600x900 screen. However when i change it to 1280x720, the right background image is trimmed. Making the centered slideshow aligned to the right.</p>
  
  <p>How do i make it trim on both side left and right while remaining the slideshow to be centered.</p>