using Aspose.Imaging;
using System;
using System.IO;
using System.Text;
using System.Collections.Generic;

//You can get all image templates from https://github.com/aspose-imaging/Aspose.Imaging-for-.NET/blob/master/Examples/Data/Templates.zip
//After download archive please unpack it and replace templatesFolder variable path with your path to unpacked archive folder
string templatesFolder = @"c:\Users\USER\Downloads\templates\";

// Load the cmx file in an instance of Image
using (var image = Aspose.Imaging.Image.Load(Path.Combine(templatesFolder, @"template.cmx")))
{
   // Create an instance of IcoOptions
   var exportOptions = new Aspose.Imaging.ImageOptions.IcoOptions();
   Aspose.Imaging.ImageOptions.VectorRasterizationOptions rasterizationOptions = new Aspose.Imaging.ImageOptions.CmxRasterizationOptions();
   rasterizationOptions.PageWidth = image.Width;
   rasterizationOptions.PageHeight = image.Height;
   exportOptions.VectorRasterizationOptions = rasterizationOptions;

   // Save cmx to ico
   image.Save(Path.Combine(templatesFolder, "output.ico"), exportOptions);

   File.Delete(Path.Combine(templatesFolder, "output.ico"));
}