Tags: images, links
Aliases: reference-links-images
Links and images in Markdown can provide the link destination or image source at the time of use or can define it elsewhere and use a label for reference. The reference format is convenient for keeping paragraph text clutter-free and makes it easy to reuse the same URL in multiple places.
There are three kinds of reference links and images:
Full: [text][label]
Collapsed: [label][]
Shortcut: [label]
Full: ![text][image]
Collapsed: ![image][]
Shortcut: ![image]
[label]: https://example.com/label
[image]: https://example.com/imageA link or image renders correctly when a corresponding label is defined, but the text displays with brackets if the label is not present. This rule warns of undefined labels for "full" and "collapsed" reference syntax.
"Shortcut" syntax is ambiguous and a missing label will not generate an error. For example,
[shortcut]could be a shortcut link or the text "shortcut" in brackets.