[puzzle]

Resizing images in Golang is not as trivial as you might imagine at first. You need to be able to handle all sorts of formats and color spaces. You'd be surprised by the kind of weird garbage your users will upload. Then you need to use SIMD, not pure Golang solutions, or performance will suffer. So you end up adopting a wrapper around libvips or similar, at which point you will start to ponder if you should have stuck with C/C++ in the first place. (It all depends on how much of Go's features you use or if it's just a nicer, safer C for you.)