First off, my sincere apologies for not replying sooner. Life is currently throwing a lot at me to do. :)

Secondly, this is not something that's high on my list, for a number of reasons. First of which being that this addresses the developer experience, while the user experience is something I'm more interested in addressing (and am working on some bugs in that realm at the moment).

That said, if you have a solution, I'm interested, but acceptance of a PR is subject to these caveats:

1. It can't break the current build process.
2. It should not introduce significantly more packages.

Let me know what you think!

No worries, I feel ya! :)

It only introduces cross-var and mkdirp. I could not get show-sizes to print nicely in one line in the last build step so I had to remove it. I'll send a PR and hope that it makes it through.

About the user experience, I also found a couple a major issues, one quite hard to spot regarding not loading the correct sized image when using async image decode with srcset.