The International Image Interoperability Framework (IIIF) defines two application programming interfaces that provide a standardised method of describing and delivering images over the web, as well as "presentation based metadata"[1] (that is, structural metadata) about structured sequences of images. If institutions holding artworks, books, newspapers, manuscripts, maps, scrolls, single sheet collections, and archival materials provide IIIF endpoints for their content, any IIIF-compliant viewer or application can consume and display both the images and their structural and presentation metadata.

via http://ronallo.com/blog/simple-interoperability-wins-with-iiif/ (planet code4lib)