Seems to copy files outside of basepath

[bkno]

I'm seeing a strange result with the below config:

require('postcss-url')({
    url: 'copy',
    basePath: path.resolve('node_modules'),
    assetsPath: 'assets/images'
    useHash: true
}),

Upon debug, bathPath is evaluated (as expected) as project_root/node_modules.

Images are not being copied from project_root/node_modules/some_lib/an_image.gif as I want however it is only copying images referenced in CSS from project_root/css into project_root/dist/assets/images.

I.e. the basePath seems to do the opposite of what it should be doing. Can anyone please explain why it is doing this?