based on this vb example I rebuild it in AutoIT http://www.vbforums.com/attachment.php?attachmentid=57693&d=1182531646 Somehow I am unable to count the difference in pixels. What am I overlooking after I press button 2. The difference should be 6397 #include <GDIPlus.au3> #include <WinAPI.au3> #include <GUIConstants.au3> #include <WindowsConstants.au3> #include <ButtonConstants.au3> #include <GUIConstantsEx.au3> #include <StaticConstants.au3>