Images and badges
Images can be inserted using  or, reference-style, ![Image][1] followed by a reference definition [1]: <http://url/b.jpg>.
More details may be found in the CommonMark documentation.
A status badge is a small image that provides at-a-glance information, for example the build status of a code repository. Badges are commonly displayed on GitHub READMEs and inserted in mdbook documentation as links to a crate’s docs.rs documentation, GitHub repo, or crates.io page. More information about badges may be found in the awesome-badges repo and in the shields.io documentation.
There is no “badge” concept in the Markdown specification. Badges are simply clickable images e.g. [  ](link-to-webpage).
mdbook-utils refdefs generate --badges creates a flat-style GitHub badge by
default. Add --badge-style flat-square, plastic, for-the-badge, or
social to choose another Shields.io style. Repository name
hyphens and underscores are escaped in the badge path so Shields.io renders
them as literal characters. The default flat style omits the style query
parameter, matching Shields.io’s default and preserving existing output for
repository names without separators.
For example, a GitHub repository named my_repo-with-dash uses this badge
image URL with the flat-square style:
https://img.shields.io/badge/my__repo--with--dash-steelblue?logo=github&style=flat-square