Images in the archive are curated by the MusicBrainz community and go through a peer review process to ensure that they are correct, free of spam and of the best quality. If you would like to contribute cover art, create a MusicBrainz account and follow the guide. To see what has been added to the archive recently, please see the Cover Art Archive page at the Internet Archive.
The Audio File Library is a C-based library for reading and writing audio files in many common formats.
The Audio File Library provides a uniform API which abstracts away details of file formats and data formats. The same calls for opening a file, accessing and manipulating audio metadata (e.g. sample rate, sample format, textual information, MIDI parameters), and reading and writing sample data will work with any supported audio file format. The Audio File Library lets you work with audio data in whatever format is most convenient for you.
TheAudioDB is a community database of audio artwork and data with a JSON API.