Use the menu on the left to browse through the albums. In the top corners you will find the following icons:
Use these icons to adjust the viewing size of the thumbnail grid to match your screen or personal preference.
Click a thumbnail to view the photo in a larger size, and use the following icons to browse backward and forward:
Return to the thumbnail grid by clicking the photo.
When you view a photo you will find the following icon on the left bottom corner which will start the slideshow: