ok, I've got into programming with python and thus far was having a fair amount of success. I've typed up a program that uses pyautogui to automates atask I need to do on a monthly basis. 
I took Screenshots of where I needed the mouse to click and when all was done I had a working program that searched the screen for the button to clicked, controlled the mouse that location, and printed out the report I needed. So, all I needed to do was plug it into the task scheduler and it would do the work for me! 
Several days afterwards, I decided to go ahead and schedule it. I ran the program again, and it crashed! Long Story short, the screen shots didn't match. I took a screen shot again, and zoomed both images 800% in Paint, and check the pixel next to the "I" in The two different images and sure enough the rgb values are different. 
I tried several other places to, and while they looked the same... The rgb values are different by maybe one or two points! I'm curious as to why is this happening!
Use confidence, default value is 0.999. Reason is pyscreeze is actually used by pyautogui which has the confidence value which most likely represents a percentage from 0% - 100% for a similarity match. Looking through the code with my amateur eyes reveals that OpenCV and NumPy are required for confidence to work otherwise a different function would be used that doesn't have the confidence value.
for example:
by doing pyautogui.locateCenterOnScreen('foo.png', confidence=0.5) will set your confidence to 0.5, which means 50%.
Pyautogui - Problems with Changing Screenshots