Exposure is a free Chrome extension which displays a different photo from Exposure every time you open a new tab.
There are a wide range of photos - cityscapes, countryside, distant views, crowds, individuals and more. Unless you've very specific tastes, "cat pictures only", you're sure to find something you like.
The extra touch here is that each photo is a part of a photo "story", a themed collection of related pictures. If it was a photo taken during a walk through a city or a day at the beach, for instance, viewing the rest of the story might show you other highlights from the same set of pictures.
If you want to explore further, there are links to view other pictures from the same photographer, and a "Shuffle" link to display another random image.