@betatim Thanks for that very comprehensive reply, which was very enlightening.
I think the issue I was facing recently was that the node I was using did not have the image and had to get a copy of it. Sometimes I was on a node with the image, and the launch time was fast.
I presume when we are talking about “images”, we are talking a Docker image. I use Docker for RStudio server based containers, i.e. using rocker as the base image, on my local machine. What is noticeable is how large they can become, e.g. up to 8-10GB. This is fine locally, but if the Rstudio binder images were nearing that size, that would explain a lot.
In terms of keeping the image size minimal, in the example Github repo mentioned above from which the image was made, the contents were quite minimal: a oneliner runtime.txt, a oneliner install.R (inst, and a small R script. The install.R was getting the tidyverse package (of packages) installed. I’m not sure if I can make anything smaller than that in terms of the repo contents. But perhaps there is a way I can make that the base Docker image being used by repo2docker to be smaller. I am new to binder, so I have not really looked into these possibilities yet, so I will try to learn more.