Sometimes, it's the little things that count. In Chrome 55, when you visit a direct link to an image, it was always displayed in the top left corner. This can make zooming and panning on the image difficult, as it is constantly locked to the corner of the screen. This was a minor annoyance at most, but Chrome 56 finally rectifies this issue.
From left to right: Firefox, Chrome 55, Chrome Dev 56
You can see this in action on Chrome Dev and Canary. While this may not be a groundbreaking change by any stretch of the imagination, it's still a nice improvement.