And... how can I set an function repeating itself until an certain image doesnt appear?

okey... so so far it works, only sometimes even when image has disapeared from screen it still keeps clicking.... my guess is that its cause my "needle.bmp" is small, like 12 pixels and probably on screen script catches these pixels somewhere else. I was wondering can I set an window like rectangle ...

Hi
I was just wondering how to make function repeating itself ( mouse clicking ) until an certain image(s) cant be found on screen/certain window.
Im all new to this, but I couldnt think of ways how to do this. Help?
Sorry for my english btw