You will see all your photos and videos on the 'Photos' tab. There are many reasons why your photos are not appear on the 'Photos' tab. If you don't see some of your photos on the 'Photos' tab, then they might be missing information about when they were taken such as date and time. Dropbox uses date and time to rearrange your photos. Normally digital photo has various information in it including date and time it was taken. If your photo's date is missing, then it will not display on Photos tab. But you can access that photo on the file browser tab. Dropbox allows you to share photos which are missing date and time and add them to albums. If you are a Dropbox for Business user, then the 'Photos' tab will only display the photos that are stored in your personal Dropbox account.