3D FlipBook - My source images have diferent formats .jpg and .png

like this:

function pageCallbackFunction(n) {
  var images = [
    'i1.jpg',
    'i2.png',
    'i3.bmp',
    'i4.gif'
  ];
  return {
    type: 'image',
    src: 'http://example.com/book1/'+images[n],
    interactive: false
  };
}