bitmap, picturebox, pixel color, image overlay, ...

Dim MyBitmap As New Bitmap(MyPicturebox.Image)

Dim MyColor As Color

MyColor = MyBitmap.GetPixel(X of your pixel, Y of your pixel)

Dim b As Bitmap

Dim cr, cg, cb As Integer

b.SetPixel(ix, iy, Color.FromArgb(cr, cg, cb))

image overlay

Imports System.Drawing

Dim OverlayImage As New Bitmap("Some Path", True)

Dim BackImage As New Bitmap("Some Path", True)

g As Graphics = Graphics.FromImage(BackImage)

g.DrawImage(OverlayImage, 0, 0)

pictureBox1.Image = BackImage