Edit in JSFiddle

var data = {
    labels: ["January", "February", "March", "April", "May", "June", "July"],
    datasets: [{
        fillColor: "rgba(220,220,220,0.5)",
        strokeColor: "rgba(220,220,220,1)",
        data: [65, 59, 90, 81, 56, 55, 40]
    }, {
        fillColor: "rgba(151,187,205,0.5)",
        strokeColor: "rgba(151,187,205,1)",
        data: [28, 48, 40, 19, 96, 27, 100]
    }]
}

var canvas = $('<canvas />');

canvas.attr({
    width: 600,
    height: 450
});

new Chart(canvas[0].getContext('2d')).Bar(data, {
    onAnimationComplete: function () {
        $('#img').attr({
            src: canvas[0].toDataURL()
        });
    }
});

<img id="img" src="" />