ConvertToIcon.cs

/// <summary>
/// Convert Image to Icon.
/// </summary>
/// <param name="image">The source image.</param>
public static Icon ConvertToIcon(Image image, bool nullTonull = false)
{
    if (image == null)
    {
        if (nullTonull) 
        { 
          return null;
        }
        
        throw new ArgumentNullException("image");
    }

    using (MemoryStream msImg = new MemoryStream()
                      , msIco = new MemoryStream())
    {
        image.Save(msImg, ImageFormat.Png);

        using (var bin = new BinaryWriter(msIco))
        {
            bin.Write((short)0);          
            bin.Write((short)1);         
            bin.Write((short)1);         

            bin.Write((byte)image.Width);  
            bin.Write((byte)image.Height); 
            bin.Write((byte)0);            
            bin.Write((byte)0);            
            bin.Write((short)0);           
            bin.Write((short)32);          
            bin.Write((int)msImg.Length);  
            bin.Write(22);                 

            bin.Write(msImg.ToArray());

            bin.Flush();
            bin.Seek(0, SeekOrigin.Begin);
            
            return new Icon(msIco);
        }
    }
}