$(document).ready(function() { //perform actions when DOM is ready
  var z = 0; //for setting the initial z-index's
  var inAnimation = false; //flag for testing if we are in a animation
  
  $('#pictures img').each(function() { //set the initial z-index's
    z++; //at the end we have the highest z-index value stored in the z variable
    $(this).css('z-index', z); //apply increased z-index to <img>
  });
	
  function swapFirstLast() {
    if(inAnimation) return false; //if already swapping pictures just return
    else inAnimation = true; //set the flag that we process a image
    
    var processZindex = z, direction = '-', newZindex = 1, inDeCrease = 1; //change for previous or next image
    
    
    $('#pictures img').each(function() { //process each image
      if($(this).css('z-index') == processZindex) { //if its the image we need to process
	    $(this).rotate({animateTo:-22});
        $(this).animate({ 'right' : 20 + 'px', 'top' : direction + $(this).height() + 'px', "width": $(this).width() - 300 + 'px'}, 'slow', function() { //animate the img above/under the gallery (assuming all pictures are equal height)
		
			$(this).rotate(0);
          $(this).css('z-index', newZindex) //set new z-index
            .animate({ 'right' : '0', 'top' : '0', "width": $(this).width() + 300 + 'px'}, 'slow', function() { //animate the image back to its original position
              inAnimation = false; //reset the flag
            });
        });
      } else { //not the image we need to process, only in/de-crease z-index
        $(this).animate({ 'top' : '0' }, 'slow', function() { //make sure to wait swapping the z-index when image is above/under the gallery
          $(this).css('z-index', parseInt($(this).css('z-index')) + inDeCrease); //in/de-crease the z-index by one
        });
      }
    });
    
    return false; //don't follow the clicked link
  }
  
  setInterval(swapFirstLast,3000);
});