C# Solution for PDF to Image Conversion

PM> Install-Package Spire.PDF

using Spire.Pdf;
using Spire.Pdf.Graphics;
using System.Drawing;
using System.Drawing.Imaging;

namespace PDFtoImage
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a PdfDocument instance
            PdfDocument pdf = new PdfDocument();

            //Load a sample PDF file
            pdf.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Input.pdf");

            //Convert the first page to an image and set the image Dpi
            Image image = pdf.SaveAsImage(0, PdfImageType.Bitmap, 500, 500);

            //Save images as JPG format to a specified folder 
            image.Save("C:\\Users\\Administrator\\Desktop\\Image\\ToImage.jpg", ImageFormat.Jpeg);

            //Close the document
            pdf.Close();
        }
    }
}

using Spire.Pdf;

namespace PDFtoSVG
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a PdfDocument instance
            PdfDocument pdf = new PdfDocument();

            //Load a sample PDF file
            pdf.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Input.pdf");

            //Convert the first page to SVG
            pdf.SaveToFile("C:\\Users\\Administrator\\Desktop\\Image\\ToImage.svg", 0, 0, FileFormat.SVG);

            //Close the document
            pdf.Close();
        }
    }
}

using System;
using System.Drawing;
using System.Drawing.Imaging;
using Spire.Pdf;
namespace SavePdfAsTiff
{
    class Program
    {
        static void Main(string[] args)
        {
            // Create a PdfDocument instance
            PdfDocument pdf = new PdfDocument();

            // Load the PDF file
            pdf.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Input.pdf");

            // Convert PDF pages to images and save them as an image array
            Image[] images = SaveAsImage(pdf);

            // Merge the converted TIFF images into a multi-page TIFF file
            JoinTiffImages(images, "C:\\Users\\Administrator\\Desktop\\Image\\ToImage.tiff", EncoderValue.CompressionLZW);
        }

        private static Image[] SaveAsImage(PdfDocument pdf)
        {
            // Create an image array with the size equal to the number of PDF pages
            Image[] images = new Image[pdf.Pages.Count];

            //Iterate through each page of PDF
            for (int i = 0; i < pdf.Pages.Count; i++)
            {
                //Convert these pages to images 
                images[i] = pdf.SaveAsImage(i);
            }
            return images;
        }

        private static ImageCodecInfo GetEncoderInfo(string mimeType)
        {
            // Get all available image encoders
            ImageCodecInfo[] encoders = ImageCodecInfo.GetImageEncoders();
            for (int j = 0; j < encoders.Length; j++)
            {
                // Find the encoder that matches the specified mime type
                if (encoders[j].MimeType == mimeType)
                    return encoders[j];
            }
            // An exception is thrown if no matching encoder is found
            throw new Exception(mimeType + " mime type not found in ImageCodecInfo");
        }

        public static void JoinTiffImages(Image[] images, string outFile, EncoderValue compressEncoder)
        {
            //Set the parameters of the image encoder
            Encoder enc = Encoder.SaveFlag;
            EncoderParameters ep = new EncoderParameters(2);
            ep.Param[0] = new EncoderParameter(enc, (long)EncoderValue.MultiFrame);
            ep.Param[1] = new EncoderParameter(Encoder.Compression, (long)compressEncoder);

            // Initialize the first image as the base for merging
            Image pages = images[0];
            int frame = 0;

            // Get the encoder information for TIFF format
            ImageCodecInfo info = GetEncoderInfo("image/tiff");

            // Iterate through each image
            foreach (Image img in images)
            {
                if (frame == 0)
                {
                    // If it's the first frame, set it as the current base image
                    pages = img;

                    // Save the first frame using the specified encoder parameters
                    pages.Save(outFile, info, ep);
                }
                else
                {
                    // For intermediate frames, update the encoder parameter to indicate a new page
                    ep.Param[0] = new EncoderParameter(enc, (long)EncoderValue.FrameDimensionPage);

                    // Save the intermediate frame
                    pages.SaveAdd(img, ep);
                }
                if (frame == images.Length - 1)
                {
                    // If it's the last frame, flush the encoder parameters to close the file
                    ep.Param[0] = new EncoderParameter(enc, (long)EncoderValue.Flush);
                    pages.SaveAdd(ep);
                }
                frame++;
            }
        }
    }
}