HI!

In order to change loader to your image, use this css:

#page-preloader.preloader-loaded .page-preloader-spin {    
background-image: URL('URL_OF_THE_IMAGE');    background-size: cover;    width: 150px;    height: 150px;    border: none;
}
#page-preloader.preloader-loaded .page-preloader-spin:before
#page-preloader.preloader-loaded .page-preloader-spin:after {    display: none;    }