See docsify-themeable's emoji demo

• https://jhildenbiddle.github.io/docsify-themeable/#/markdown?id=emoji

It appears the CDN used for emoji images is having issues or is no longer used for this purpose by GitHub.

For example, this markdown:

Is rendered as follows by docsify:

<img class="emoji" src="https://assets-cdn.github.com/images/icons/emoji/thumbsup.png" alt="thumbsup">

Here's how tne same emoji is rendered as part of a GitHub issue:

<g-emoji class="g-emoji" alias="+1" fallback-src="https://github.githubassets.com/images/icons/emoji/unicode/1f44d.png">👍</g-emoji>

Note the rendering method (rendering an actual emoji character) and the use of a different URL as a fallback. The official unicode emoji list may be helpful if/when docsify's emoji output is updated.