The wiki pages live in this repository's wiki, imported from the former MediaWiki at https://docs.einsteintoolkit.org/et-docs/.
Images and other attachments are stored in assets/ in the wiki git
repository, not in this repo. Clone that with:
git clone git@github.com:EinsteinToolkit/wiki.wiki.git
Then add files under assets/ and reference them from wiki pages as:
https://raw.githubusercontent.com/wiki/EinsteinToolkit/wiki/assets/NAME