Image.FromStream 将采取流，并返回一个图像。顺便说一句，如果你使用 Bitmap.FromStream 或 Image.FromStream ，或任何这些方法，它们都返回位图，所以他们都可以上溯造型到位图从图片如果你想让他们。

Image.FromStream will take a stream and return an image. Incidentally, if you use Bitmap.FromStream or Image.FromStream, or indeed any of these methods, they all return a Bitmap, so they can all be upcast to Bitmap from Image if you want them to be.