How to build an image without building the toolchain?

I thought the SDK would be suitable for this, but it doesn't generate the images / firmware files.

Also, do you plan to include the ImageBuilder in downloads?

But, the imagebuilder is there? https://downloads.lede-project.org/snapshots/targets/ar71xx/generic/lede-imagebuilder-ar71xx-generic.Linux-x86_64.tar.xz

Sorry, no idea how I missed it.