Hey @Kurt-von-Laven Currently, users can only bring their own Docker images. All machine-type executors (windows included) do not have the ability to specify an AMI or custom machine image.
You can actually do this if you are using the CircleCI Enterprise (Server) product.
Users on the Scale plan can also utilize the “Runner” product to run their CircleCI job locally on their own custom hardware.
For cloud users, our general recommendation is to use Orbs to install any extra dependencies you may have. This might also be more efficient in some cases than it would be to bring your own image when you factor in pre-booted VMs (which often launch instantly) vs consistently cold booting.