One Photo Viewer is a simplistic and intuitive photo viewer. Free with no ads. It is designed to be used as Windows default photo viewer app. It has some basic features such as slideshow, color adjustment, crop, resize, rotate and copy/paste clipboard. All accessible by right click menu or keyboard shortcuts. It is also touchscreen compatible. For Windows 10 users it's recommended to download the app from Microsoft Store to benefit from automatic updates and better Windows integration.