This Week I Learned
http://tldr.sh (friendlier version of
manon the command line)
In Github comments/PR descriptions, you can have collapsible sections that work pretty well for not cluttering the PR when you have multiple screenshots.
<details> <summary>Mobile Preview</summary> <img src="http://via.placeholder.com/350x150" /> </details>
Cloudflare has a super clever way of generating random hashes: