Alright, so for all of you... I dont think I did a good job explaining. lets say you change the url in the script to "C:\Users\MyName\Pictures\AutoItPics\"
This implies that:
"C:\Users\MyName\Pictures\AutoItPics\MainMenu.png" is valid. Basically it means that the actual PNGs are in the AutoItPics folder.
Once you can confirm that, we can move on... but this is usually the mistake that is made, and in fairness... I could have explained it better the first time.