Template is using retina.js script which replaces all of your images that are placed in HTML code. You need to make two sizes of images. First, default one that will be displayed on normal screens will be named image.jpg, for example and retina image will be named firstname.lastname@example.org. Images needs to be placed in the same folder.
Changing main color of the template is quite simple. Just open defaultcolor.css file and replace the color with your own. Kreator comes with few predefined color styles so you can use one of them too. All icons that are in color are made with font icons so there’s no need of coloring icons in image editors. Everything is done in just one click.