You should actually read the details page before criticizing the project. It does none of the things you say. In fact the technique is very similar to the one detailed in the ALA article.
Yes, it says the requirements are Apache 2, PHP 5.x, and GD lib. I would call those specific server-side technologies.
But it doesn't "load two images, load no images when JavaScript is disabled, depend on userAgent sniffing". The only reason PHP or GD is needed is to automatically generate alternate image sizes, which the ALA author does manually.