pixels.js

 function chooseMode(jsProps, cssProps) {
        if (cssProps.length == 0 && jsProps.length == 0)  // IE <10, other early browser, no method works there. In Opera CSS works though
            return bowser.opera ? 'css' : 'warning';
        if (cssProps.length == 0 && jsProps.length > 0)  // IE >10 even EDGE... sigh
            return 'js';
        if (cssProps.length == 1 && cssProps[0] == 'optimiseSpeed' && jsProps.length == 0) //A few earlier browsers report this prop, but it only works for images
            return 'warning';
        if (_.includes(cssProps, '-webkit-optimize-contrast') || _.includes(cssProps, '-moz-crisp-edges') || _.includes(cssProps, 'crisp-edges') || _.includes(cssProps, 'pixelated')) {
            if (!bowser.check({chrome: "41"})) //Earlier chromes only support css on IMG
                return 'js';
            return 'css';
        }
        return 'warning';
    }