A management system gives an instruction to assign a value of an attribute corresponding to an environment where a processing system including a virtual machine started using a system image file is constructed, to the system image file, determines, based on a condition according to the value of the attribute assigned to the system image file in response to the instruction, whether the system image file is to be deleted, and gives an instruction to delete, from a storage device, the system image file that has been determined to be deleted.