Bit off-topic, but... it feels like there's a trend towards "x as a service" away from "x as open-source software". Is that something other people are seeing, or is it just my imagination?
This is actually also an OS project it appears: https://github.com/asm-products/firesize
Firesize uses ImageMagick, which in my experience consumes more memory and is slower than libvips [1] for simple image resizing/optimization.
I built a simple image-resizing server with a query string API using libvips [2]. This is based on sharp [3], a good wrapper of libvips for Node.js.
[1] https://github.com/jcupitt/libvips