Is it possible to create these .gifs from within Quirk? Or does one need to use some third-party software?
I made those GIFs using the screen recorder ScreenToGif.
ScreenToGif is not very good at compressing while maintaing quality, so I found it worked better to disable all optimizations while recording, try to preserve all detail, then post-process using GIMP's "Optimize (for GIF)" filter. GIMP is also handy for e.g. adding the text labels you see in the images.