Flickr allows you to create a photo or video gallery. It is used to showcase your photos. You can add other people's or photographers photos and videos to your Flickr gallery. You can not add your own photos and videos to Flickr gallery. Flickr allows you to add your photos in 'Sets' or 'Albums'. You can edit a gallery, change the title and description, remove items, add notes and move things around using the Action menu. You can change the featured photo or video for a Flickr gallery. To do this, open the gallery and click, drag and drop the thumbnail of the photo from the right hand side, over the featured photo on the left hand side.
You can install PicBackMan's Flickr uploader for Mac from the website and start backing up photos and videos.