Custom images sizes for Smush

WordPress has several default image dimensions it creates when you upload images to the media library. Plugins like WooCommerce add their own dimension to that. I think it would be great if we could specify our own image dimension so that Smush can automatically resize uploaded images to those dimensions as well. I know we currently have the option to specify a max width and height, but this would be different in that we could specify any sizes we want.