Instagram is an online mobile photo-sharing, video-sharing, and social networking service that enables its users to take pictures and videos, and share them either publicly or privately on the app, as well as through a variety of other social networking platforms, such as Facebook, Twitter, Tumblr, and Flickr. Originally, a distinctive feature was that it confined photos to a square shape, similar to Kodak Instamatic and Polaroid images, in contrast to the 4:3 aspect ratio typically used by mobile device cameras. In August 2015, version 7.5 was released, allowing users to post photos captured in any aspect ratio. Users can also apply digital filters to their images. The maximum duration for Instagram videos is 15 seconds.