This specification defines a protocol for retrieving image data from a variety of astronomical image repositories through a uniform interface. The interface is meant to be reasonably simple to implement by service providers. A query defining a rectangular region on the sky is used to query for candidate images. The service returns a list of candidate images formatted as a VOTable. For each candidate image an access reference URL may be used to retrieve the image. Images may be returned in a variety of formats including FITS and various graphics formats. Referenced images are often computed on the fly, e.g., as cutouts from larger images.
@article{arxiv.1110.0499,
title = {IVOA Recommendation: Simple Image Access Specification Version 1.0},
author = {Doug Tody and Ray Plante and Paul Harrison},
journal= {arXiv preprint arXiv:1110.0499},
year = {2019}
}