Change preloader

This is what you need to add to use your own preloader

.preloader .pre-bounce1, .preloader .pre-bounce2 {
   display: none;
}
.preloader .spinner {
   background-image: url('http://yoursite.com/path/to/image.gif');
   width: 30px;
   height: 30px;
   background-repeat: no-repeat;
   background-size: contain;
}