function renderImageToDataURL(img, blob, options, doSquash) {
        var canvas = document.createElement("canvas"),
            mime = options.mime || "image/jpeg",
            promise = new qq.Promise();

        renderImageToCanvas(img, blob, canvas, options, doSquash)
            .then(function() {
                promise.success(
                    canvas.toDataURL(mime, options.quality || 0.8)
                );
            });

        return promise;
    }
Rendering image element (with resizing) and get its data URL