If you want to use ressources included in the .exe, I would strongly recommend that you use RessourceEX UDF, unless you want to reinvent the wheel. The example provided show you how to add different resources. But if you only need icon to a button, you can do it like this :
#AutoIt3Wrapper_Res_Icon_Add=%AUTOITDIR%\Examples\Helpfile\Extras\Soccer.ico
#include <GUIConstantsEx.au3>
#include <WindowsConstants.au3>
#include <ButtonConstants.au3>
Local Const $iHeight = 450, $iWidth = 470
$g_hGUI = GUICreate('Resources Example', $iWidth, $iHeight, Default, Default, BitOR($GUI_SS_DEFAULT_GUI, $WS_MAXIMIZEBOX, $WS_SIZEBOX))
Local $iBall = GUICtrlCreateButton('Click', $iWidth - 168, 72, 68, 71, $BS_ICON)
GUICtrlSetImage($iBall, @AutoItExe, '201') ; Icon resources added with #AutoIt3Wrapper_Res_Icon_Add, can be directly used without the UDF.
Global $picIcon = GUICtrlCreateIcon(@AutoItExe,201,100,10,32,32)
GUISetState(@SW_SHOW, $g_hGUI)
While True
Switch GUIGetMsg()
Case $GUI_EVENT_CLOSE
ExitLoop
EndSwitch
WEnd
You will need to compile the script first...