Flickr received attention earlier this year when it began offering 1 TB of free photo storage space and underwent a major design overhaul. As previously speculated, Flickr is also now integrated within iOS 7, as users can choose to share photos directly to Flickr from the Photos app or various third-party apps with the functionality.
The last major update to Flickr for iOS came in August, when live filters and professional editing capabilities were added to the app. Flickr is a free download on the App Store. [Direct Link]