SIZE parameter does not work for ISO built boxes

[wzzrd]

Creating a box from a RHEL 7.2 ISO file whilst the SIZE parameter is set to 15 will still give you an image of 40G. For pre-made boxes (e.g. centos-7.2), the parameter does work.

[purpleidea]

By default boxes should all be 40G... Can you provide more information on what you're trying to accomplish?