New Post: Convert a pdf page to image

The conversion works fine now and this is the function I used to do the conversion action and at the same time it returns to me the new name of the converted image

private string convertPdf(string file)

     {
         string newPathImage = "";

         MagickImageCollection collection = new MagickImageCollection();

         MagickReadSettings settings = new MagickReadSettings();

         settings.Density = new MagickGeometry(144, 144);

         collection.Read(file, settings);

         int id = 0;

         foreach (MagickImage image in collection)
          {
            image.Write(file+ "img" + id + ".png");

            newPathImage = image.ToString();

             id++;
          }

          return newPathImage;
     }

the problem when I want to open newPathImage in other action , an error occur "can not open the file "imagepdf.pdfimg0.png"