If you have an application that allows users to upload their own photos, it can be very useful to be able to organize these photos according to their content. This will allow you to categorize the content for displaying to all your users and make your image library searchable. Furthermore, you can also learn more about your users according to the content they upload and find different trends of what people care about. Other added benefits can also include the ability to display matching content to your users according to their interests or even match them with other users that share similar interests.
Many social networks, websites and messaging applications allow users to upload a wide variety of media files, and although the majority of files are in the form of images and video clips, a significant minority are audio files. When the website or application subsequently needs to display a thumbnail that describes the uploaded content, images can be cropped and resized down to scale, and a single frame from a video clip can be converted to an image and then also cropped and resized down to scale.