When a slideshow is used the next image will automatically appear without having to click on anything. You can set slideshows to change at different times. Normally, a slideshow will change every 3 - 5 seconds.
One can sometimes view photos on some social networking sites or blogs. You can opt to view it sometimes as a slideshow, or you can also view the photos at your own pace and click on the next image. One can also opt to leave a comment, and this can have a label such as comment added on, which indicates the time and date of the comment post. There would also sometimes be a heading that states, Your Comment.