This documentation is not using the current rendering mechanism and is probably outdated. The extension maintainer should switch to the new system. Details on how to use the rendering mechanism can be found here.
YAG is capable to generate RSS a RSS feed from your image list. To include the feet into your template add the following configuration to yor theme typoscript:
plugin . tx_yag . settings . themes . default . feed . active = 1
Visit the typoscript reference for a detail description of the rss configuration options.