How to export the PDF document into images in ASP.NET Core using Pdfium rendering engine?

static void Main(string[] args)
        {
            PdfiumViewer.FPDF_AddRef();
 //Get the stream of the PDF document
            Stream input = File.OpenRead("../../../Data/HTTP Succinctly.pdf");
            int id = StreamManager.Register(input);
            IntPtr doc = PdfiumViewer.FPDF_LoadCustomDocument(input, null, id);
            PdfiumViewer.FPDF_GetDocPermissions(doc);
            PdfiumNative.PdfRenderFlags flags = PdfiumNative.PdfRenderFlags.CorrectFromDpi;
            int pageCount = PdfiumViewer.FPDF_GetPageCount(doc);
       
            for (var i = 0; i < pageCount; i++)
            {
                double width;
                double height;
    //Get the size of the PDF document page
                int pagesizes = PdfiumViewer.FPDF_GetPageSizeByIndex(doc, i, out width, out height);
                int Width = (int)width;
                int Height = (int)height;
                int rotation = 0;
                IntPtr pages = PdfiumViewer.FPDF_LoadPage(doc, i);
    //Creating new bitmap image
                Bitmap bitmapImage = new Bitmap(Width, Height);
                BitmapData data = bitmapImage.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, bitmapImage.PixelFormat);
                IntPtr createdpages = PdfiumViewer.FPDFBitmap_CreateEx(Width, Height, 4, data.Scan0, bitmapImage.Width * 4);
                uint background = (flags & PdfiumNative.PdfRenderFlags.Transparent) == 0 ? 0xFFFFFFFF : 0x00FFFFFF;
                PdfiumViewer.FPDFBitmap_FillRect(createdpages, 0, 0, Width, Height, background);
                PdfiumViewer.FPDF_RenderPageBitmap(createdpages, pages, 0, 0, Width, Height, rotation, 0);
                PdfiumViewer.FPDFBitmap_Destroy(createdpages);
                bitmapImage.UnlockBits(data);
                bitmapImage.Save("../../../Images/" + "exportedPage11_" + i.ToString() + ".png");
            }
        }