The Artstor Digital Library provides more than two million images with tools for teaching and research. Its over 300 collections comprise contributions from outstanding museums, photographers, libraries, scholars, photo archives, artists and artists' estates from all over the world. With the integration of Artstor into the JSTOR platform, Artstor’s images are searchable alongside JSTOR’s image collections, full-texts and other media. Being also accompanied by high-quality metadata furthermore helps situating Artstor’s images in a historical, critical or cultural context.

arXiv is an e-print service in the fields of physics, mathematics, computer science, quantitative biology, quantitative finance, statistics, electrical engineering and systems science, and economics. It provides access to more the 1.3 million e-prints. The Max Planck Society is a member institution of arXiv.

prometheus is a digital image archive for Art and Cultural Sciences containing approx. 360.000 images -- prometheus ist ein digitales Bildarchiv für Kunst- und Kulturwissenschaften mit ca. 360.000 Bildern

Zenodo is an open data repository, developed and operated by CERN. It is an catch-all repository, that welcomes research from all over the world, and from every discipline. Zenodo does not impose any requirements on format, size, access restrictions or licence. A digital object identifier (DOI) is automatically assigned to all Zenodo files and it is integrated into reporting for research funded by the European Commission.