Nice, but... it's not actually minimal. But nice.

Also a bit of nitpicking. While it provides a visual placeholder for an image that's being fetched, it does not reflect its content. So, when it's loaded we can see a completely different color palette and shapes.

I see two issues, let's say "opportunities":

First is the limitation to one hue value. Something like the Sunflower (blue + yellow) is just yellow. Maybe there's a tradeoff that could pack more hue but with less luminescence.

The second is how the primary color is selected. Several images (plant on grey background, street food vendor) appear to be averaging across the image and getting a grey value. By selecting better for the predominant color and its placement, the greys would appear on their own.

What do you mean? In my opinion this library does a very good job of representing the image’s color palette considering it’s encoded into a single integer. (Even smaller than usual because of CSS limitations, only 20 bits!)

You don’t even need JavaScript to decode that integer into the image. The underlying CSS may be complex, but for the user of the library it definitely feels minimal in a good way.

That's pretty much an issue with every LQIP solutions though, including BlurHash and ThumbHash. The only thing that matters is that it's close enough to the real thing, since they're meant to serve as placeholders.