using System;
using System.Collections.Generic;
using System.Drawing;
namespace Get_Color_Count_From_Image
{
    class Program
    {
        static void Main(string[] args)
        {
            var img = Image.FromFile("image.png");
            List<Color> colors = new List<Color>();
            using (Bitmap bmp = new Bitmap(img))
            {
                for (int i = 0; i < bmp.Width; i++)
                {
                    for (int j = 0; j < bmp.Height; j++)
                    {
                        Color clr = bmp.GetPixel(i, j);
                        if (colors.IndexOf(clr) == -1)
                        {
                            colors.Add(clr);
                        }
                    }
                }
            }
            Console.WriteLine(colors.Count);
            Console.ReadKey();
        }
    }
}