Can someone explain the BitmapData.Scan0 property?

This property is a strange one, I made two copies of a bitmap file, included both files as resources, and loaded the resources into bitmap and bitmapdata objects as follows:

        Dim b As New Bitmap(My.Resources.pic1)     ' from bmp file pic1
        Dim b2 As New Bitmap(My.Resources.pic2)   ' from exact copy of pic1 picture file

        Dim r As New Rectangle(0, 0, b.Width, b.Height)

        Dim bd As BitmapData
        bd = b.LockBits(r, ImageLockMode.ReadOnly, b.PixelFormat)
        Dim bd2 As BitmapData
        bd2 = b2.LockBits(r, ImageLockMode.ReadOnly, b2.PixelFormat)

I was trying to cheat and do an Equals on the two bitmapdata objects to see if they were the same picture, but they turn out to be unequal.  Putting a breakpoint after the above, code,I see that the only difference is the Scan0 property, for which one has a value of 62935008 and the other has a value of 62944688.  I guess I don't really understand what this property is, and how they ended up different.  MSDN says Scan0:

"Gets or sets the address of the first pixel data in the bitmap. This can also be thought of as the first scan line in the bitmap."

I read this and assumed that it was an address relative to the first byte of the object, maybe a header length or something.  It would seem weird if it was its own actual location in memory... does anyone know for sure?