Edit in JSFiddle

    function ready() {
        var imgSource = document.getElementById('google_logo');
        var canvas = document.createElement('canvas');
        canvas.id = 'myCanvas';
        var ctx = canvas.getContext('2d');
        canvas.setAttribute('width', imgSource.width);
        canvas.setAttribute('height', imgSource.height);
        ctx.drawImage(imgSource, 0, 0);
        document.getElementsByTagName('body')[0].appendChild(canvas);
    }
    window.addEventListener('DOMContentLoaded', ready, false);

Source：<br><img src="https://www.google.com/images/errors/logo_sm.gif" alt="Google" id="google_logo"><br>
    Copy：<br>