[WP8] Application.CaptureScreenshot() image not shown in gallery

I already called the Application.CaptureScreenshot() function, and log the destination path of the image, persistent data path + filename. But the image is not show up in the gallery. I had similar problem in Android and iOS before, and I have to refresh the gallery to index the new generated image. Is this step is necessary in WP8 too? Or, maybe the function simply not generating the screenshot?