XNA 和从文件加载图像

我找到了直接从文件加载图像的方法，但我加载的图像是蓝色的（原始图像是绿色的）。我坚持认为它以不好的方式保存，所以我用 photoshop 保存了它，但没有任何变化。我想我的程序运行不佳。如何更改它，这是从文件加载图像的好方法吗？位图到纹理2d方法：

    public static Texture2D GetTexture2DFromBitmap(GraphicsDevice device, Bitmap bitmap)
    {
        Texture2D tex = new Texture2D(device, bitmap.Width, bitmap.Height);
        System.Drawing.Imaging.BitmapData data = bitmap.LockBits(new System.Drawing.Rectangle(0, 0, bitmap.Width, bitmap.Height), System.Drawing.Imaging.ImageLockMode.ReadOnly, bitmap.PixelFormat);
        int bufferSize = data.Height * data.Stride;
        byte[] bytes = new byte[bufferSize];
        System.Runtime.InteropServices.Marshal.Copy(data.Scan0, bytes, 0, bytes.Length);
        tex.SetData(bytes);
        bitmap.UnlockBits(data);
        return tex;
    }

加载图像行：

        backgroundTexture = Tools.GetTexture2DFromBitmap(device, (System.Drawing.Bitmap)System.Drawing.Image.FromFile(@"1.bmp", false));

绘制纹理方法：

        spriteBatch.Begin();
        Rectangle screenRectangle = new Rectangle(0, 0, screenWidth, screenHeight);
        spriteBatch.Draw(backgroundTexture, screenRectangle, Color.White);
        spriteBatch.End();