Bulkr is a Mac application that provides you with an easy yet efficient way to back up pictures and videos uploaded to your Flickr account. You can also use this program to fetch photos and clips that were posted by other users on the aforementioned website.
After you log in to your Flickr account from the app's interface, you can start using the integrated search tool to find the pictures or videos you wish to download to your local drives. This utility also enables you to browse media files that were posted X days ago and fetch the ones you need.
Another thing I like about this program is that it allows you to download photos at any resolution you require. After you click the Download button, the app lets you choose between 4 different sizes (Small, Medium, Large, and Original) and offers you an option to embed metadata onto the fetched pictures.
My only beef with this download manager is that you need to pay a certain amount of money to be able to use all of its built-in features (browse up to 500 photos per page, sort media files, etc.).
As a conclusion, it's worth acquiring Bulkr only if the aforementioned flaws don't mean much to you. Otherwise, I'd suggest you to try other download managers to fetch pictures and clips from Flickr website.