How can I get the icon from the executable file only having an instance of it's Process in C#

Solution 1:

Icon ico = Icon.ExtractAssociatedIcon(theProcess.MainModule.FileName);

Solution 2:

This is a sample from a console application implementation.

using System;
using System.Drawing;         //For Icon
using System.Reflection;      //For Assembly

namespace ConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                //Gets the icon associated with the currently executing assembly
                //(or pass a different file path and name for a different executable)
                Icon appIcon = Icon.ExtractAssociatedIcon(Assembly.GetExecutingAssembly().Location);                
            }
            catch(ArgumentException ae) 
            {
                //handle
            }           
        }
    }
}

Solution 3:

Use the ExtractIconEx (and here) p/invoke. You can extract small and large icons from any dll or exe. Shell32.dll itself has over 200 icons that are quite useful for a standard Windows application. You just have to first figure out what the index is for the icon(s) you want.

Edit: I did quick SO search and found this. The index 0 icon is the application icon.