You may notice that my Twitter cover changes every day and night (in my timezone, of course). The images were from Unsplash and Nasa.

Answer: I developed https://github.com/ThewApp/auto-twitter-cover and deployed it with Docker .

You can look at the source code. It only has 224 lines.

Previously, I wrote it in Node.js, but last week I rewrote it in Go . The docker image size reduced from hundreds of MB to 30 MB, and the idle memory usage went down from 50 MB to 6 MB .