ISO/IEC 20071-11:2019

This document gives guidance on how to create text alternatives and what information to put in text alternatives.
This document applies to all static images that are used in any type of electronic document. It also applies to individual images within a slide show.
This document does not apply to moving images (e.g. movies).
NOTE 1 While text alternatives can be implemented via various mechanisms in various types of electronic documents, the contents of this document are not dependent on the choice of implementation mechanism or of electronic document type.
NOTE 2 Guidance on making moving images accessible is contained in ISO/IEC TS 20071-21, ISO/IEC 20071-23 and ISO/IEC 20071-25.