Try this,
It will help you.
Dim btmp as Bitmap = Image.FromFile("Your File Path")
Dim clr as Color = btmp.GetPixel(New Point(100,0))
Here clr will have the color at the Point (100,0). You can change it as your wish.
If you want to compare it in the whole image then you can do it using for loop by just changing the point.
Thanks.