How do I grab a program's DWM thumbnail from it's process handle in .NET 6.0 WPF C#

Question

I am trying to recreate the Flip3D feature from Windows Vista (pictured below), but now I need to get the DWM thumbnails from each program. I already have each program's process handle, but now I need to grab their thumbnails and convert them into a BitmapImage so I can use them as Image sources.

I did some digging, and found this thread that helped a little, but it uses "WindowInfo" to grab the thumbnail, which doesn't exist. I need to use the process handle. If anyone could help that would be nice.

        [DllImport("dwmapi.dll", PreserveSig = false)]
        private static extern bool DwmIsCompositionEnabled();

        [DllImport("dwmapi.dll")]
        private static extern int DwmExtendFrameIntoClientArea(IntPtr hWnd, ref MARGINS pMargins);
        [StructLayout(LayoutKind.Sequential)]
        struct MARGINS
        {
            public int Left;
            public int Right;
            public int Top;
            public int Bottom;

            public void ExtendToWholeClientArea()
            {
                this.Left = -1;
                this.Right = -1;
                this.Top = -1;
                this.Bottom = -1;
            }
        }
        [DllImport("dwmapi.dll")]
        private static extern int DwmRegisterThumbnail(IntPtr dest, IntPtr src, out IntPtr thumb);

        [DllImport("dwmapi.dll")]
        private static extern int DwmUnregisterThumbnail(IntPtr thumb);

        [DllImport("dwmapi.dll")]
        private static extern int DwmQueryThumbnailSourceSize(IntPtr thumb, out PSIZE size);

        [StructLayout(LayoutKind.Sequential)]
        private struct PSIZE
        {
            public int x;
            public int y;
        }
        [DllImport("dwmapi.dll")]
        private static extern int DwmUpdateThumbnailProperties(IntPtr hThumb, ref DWM_THUMBNAIL_PROPERTIES props);

        [StructLayout(LayoutKind.Sequential)]
        private struct DWM_THUMBNAIL_PROPERTIES
        {
            public int dwFlags;
            public RECT rcDestination;
            public RECT rcSource;
            public byte opacity;
            public bool fVisible;
            public bool fSourceClientAreaOnly;
        }
        [StructLayout(LayoutKind.Sequential)]
        private struct RECT
        {
            public RECT(int left, int top, int right, int bottom)
            {
                Left = left;
                Top = top;
                Right = right;
                Bottom = bottom;
            }

            public int Left;
            public int Top;
            public int Right;
            public int Bottom;
        }
        private static readonly int DWM_TNP_VISIBLE = 0x8;
        private static readonly int DWM_TNP_RECTDESTINATION = 0x1;
        private static readonly int DWM_TNP_SOURCECLIENTAREAONLY = 0x00000010;