RT/Metro商店应用如何如何获取图片的宽高
var file = await StorageFile.GetFileFromApplicationUriAsync(new Uri("ms-appx:///Assets/test.jpg", UriKind.RelativeOrAbsolute));
ImageProperties imageProperties = await file.Properties.GetImagePropertiesAsync();
canvas.Width = imageProperties.Width;
canvas.Height = imageProperties.Height;