Detect corrupted charts

suspector.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Linq;

namespace TooMuchWhite
{
    class Program
    {
        static void Main(string[] args)
        {
            var files = Directory.EnumerateFiles(@"C:\Users\rrusu\Desktop\last check", "924.png", SearchOption.AllDirectories);
            //var files = Directory.EnumerateFiles("Samples");

            var cntr = 0;

            Console.WriteLine("Files to process " + files.Count());

            foreach (var file in files)
            {
                cntr++;

                if (cntr%10 != 0)
                    Console.Write(".");
                else
                    Console.Write(cntr);

                var suspectCorrupted = IsSuspiciousEnough(file);

                if (suspectCorrupted)
                    Console.WriteLine("\t " + file);
            }

            Console.ReadKey();
        }

        private static bool IsSuspiciousEnough(string file)
        {
            bool suspectCorrupted;

            using (var image = Image.FromFile(file))
            using (var bmp = GrayScale(new Bitmap(image)))
            {
                var colors = new Dictionary<Color, int>();

                for (int i = 0; i < image.Height; i++)
                {
                    for (int j = 0; j < image.Width; j++)
                    {
                        var nowColor = bmp.GetPixel(j, i);

                        if (colors.ContainsKey(nowColor))
                            colors[nowColor]++;
                        else
                            colors[nowColor] = 1;
                    }
                }

                var tops = colors.OrderByDescending(x => x.Value).Take(3);

                var white = Color.White;
                var topColor = tops.First().Key;
                var total = image.Height*image.Width;
                var inRatioOf = (int) Math.Round((double) (100*tops.First().Value)/total);

                var topColorIsWhite =
                    white.A == topColor.A &&
                    white.R == topColor.R &&
                    white.G == topColor.G &&
                    white.B == topColor.B;

                suspectCorrupted = topColorIsWhite && inRatioOf > 90;

                /*else
                    {
                        Console.WriteLine(file);
                    }*/

                /*foreach (var color in tops)
                    {
                        var colorPerc = (int)Math.Round((double)(100 * color.Value) / total);
                        Console.WriteLine("\t " + colorPerc + "% " + color.Key + " " + color.Value);
                    }
                    Console.WriteLine();
                     */
            }

            return suspectCorrupted;
        }

        public static Bitmap GrayScale(Bitmap Bmp)
        {
            int rgb;
            Color c;

            for (int y = 0; y < Bmp.Height; y++)
                for (int x = 0; x < Bmp.Width; x++)
                {
                    c = Bmp.GetPixel(x, y);
                    rgb = (int)((c.R + c.G + c.B) / 3);
                    Bmp.SetPixel(x, y, Color.FromArgb(rgb, rgb, rgb));
                }
            return Bmp;
        }
    }
}