The web sucks if you have a slow connection
Something I have had at the back of my mind for a long time: in 2017, what's the correct way to present optional resources that will improve the experience of users on fast/uncapped connections, but that user agents on slow/capped connections can safely ignore? Like hi-res hero images, or video backgrounds, etc.Every time a similar question is posed on HN, someone says "If the assets aren't needed, don't serve them in the first place", but this is i) unrealistic, and ii) ignores the fact that while the typical HN user may like sparsely designed, text-orientated pages with few images, this is not at all true of users in different demographics. And in those demos, it's often not acceptable to degrade the experience of users on fast connections to accommodate users on slow connections.So -- if I write a web page, and I want to include a large asset, but I want to indicate to user agents on slow/capped connections that they don't _need_ to download it, what approach should I take?