Albums are the easiest way to organize & share a bunch of photos and videos. Dropbox allows you to create an album on its Photos page. To do this, Sign In to the Dropbox website & click 'Photos' located at left side of the window. Click on the photos which you want to be in the album. A blue border and checkmark will appear on each selection. Click "..." (3 horizontal dots) located at the top right side corner of the window & select "Add to Album" option. You will be prompted 'Choose an album' window. Click 'Create new album' & enter the album name. This is how you create an album in Dropbox on Photos page.
You can install PicBackMan's Dropbox uploader for Mac from the website and start backing up photos and videos.