Thanks, Mike. I played around with all the Image Size settings, but unfortunately my images were still zooming in just a tad bit too slightly.
It looks like this line of CSS was causing the issue
.wp-tiles-tile-bg{background-size: cover;}
I modified this to:
.wp-tiles-tile-bg{background-size: 100% 100%;}
And, that seems to have done the trick so that my tile images are appearing at their original size.