Click on View, Header and Footer, and under Include on slide, check mark
Date and time and Update automatically.
If you don't like where Microsoft places your date, then click on View,
Master, Slide Master and move the date place holder to anywhere you would
like it to appear on all you slides.
This being said, if you move it to the middle of the screen an then put you
picture in, it will not appear. You will have to put your pictures as
background images on the slide.