Add photos and videos to an existing album by clicking on the edit button on top, then choose 'photos and videos under the 'add' button (or from the side bar if you are using the old editor).
High quality
Photos and videos in albums on the free Basic account are stored in high quality.
Group albums
MyAlbum also offers 'group albums', click on the 
top right to add your photos and videos and select 'contribute...'. The album owner will receive a request to approve or disapprove the photos and videos.