C# 判断两张图片是否一致的快速方法

#region 判断图片是否一致   
/// <summary>   
/// 判断图片是否一致   
/// </summary>   
/// <param name="img">图片一</param>   
/// <param name="bmp">图片二</param>   
/// <returns>是否一致</returns>   
public bool IsSameImg(Bitmap img, Bitmap bmp)   
{   
//大小一致   
if (img.Width == bmp.Width && img.Height == bmp.Height)   
{   
//将图片一锁定到内存   
BitmapData imgData_i = img.LockBits(new Rectangle(0, 0, img.Width, img.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);   
IntPtr ipr_i = imgData_i.Scan0;   
int length_i = imgData_i.Width * imgData_i.Height * 3;   
byte[] imgValue_i = new byte[length_i];   
Marshal.Copy(ipr_i, imgValue_i, 0, length_i);   
img.UnlockBits(imgData_i);   
//将图片二锁定到内存   
BitmapData imgData_b = img.LockBits(new Rectangle(0, 0, img.Width, img.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);   
IntPtr ipr_b = imgData_b.Scan0;   
int length_b = imgData_b.Width * imgData_b.Height * 3;   
byte[] imgValue_b = new byte[length_b];   
Marshal.Copy(ipr_b, imgValue_b, 0, length_b);   
img.UnlockBits(imgData_b);   
//长度不相同   
if (length_i != length_b)   
{   
return false;   
}   
else   
{   
//循环判断值   
for (int i = 0; i < length_i; i++)   
{   
//不一致   
if (imgValue_i[i] != imgValue_b[i])   
{   
return false;   
}   
}   
return true;   
}   
}   
else   
{   
return false;   
}   
}   
#endregion