I think it's really weird that this is considered. Masonry is a very specific layout implementation whilst the typical CSS layout feature is more foundational.

I think it's really weird that this is considered. Masonry is a very specific layout implementation whilst the typical CSS layout feature is more foundational. Also, I think the need for masonry is vastly overestimated or perhaps not fully researched. It is presented/implied to be a common need but it isn't. Check the top 100 websites, check your personal top 20 websites, how many use masonry? I bet not that many, it's niche use case which also has plenty of usable alternatives. It also never even shows up in any developer surveys. Anyway, if we're into the game of building very specific layout solutions into CSS itself now, I'd argue the layout as seen on Google Image search is the far more useful one. It is somewhat of a horizontal masonry, but not really. Each image must keep its original aspect ratio (no cropping) whilst all images on the same row have the same height, thus filling the vertical space of the row fully. At the same time, rows must be roughly of the same height. There can be no gaps at the end of a row nor at the last row. Quite hard to implement, although there's articles describing how.