图片比较是否相同的方案

http://blog.youkuaiyun.com/luqc1985/article/details/3658667

通过Hash值来判断是否相同

[CLSCompliant(false)] 
    public static uint GetBitmapHashValue( 
      Bitmap image) 
    { 
      uint result = 0xFFFFFFFF;

      for (int x = 0; x < image.Width; x++) 
        for (int y = 0; y < image.Height; y++) 
          result = 
            BitmapHasher.CRCTable[ 
            (result ^ image.GetPixel(x, y).ToArgb()) & 0xFF] ^ 
            (result >> 8);

      return result ^ 0xFFFFFFFF; 
    }