1. An image-forming system comprising: a plurality of image-forming devices connected to a network, each image-forming device being selectively capable of performing a test print process to form a test image and an image print process to form an image based on image data, each image-forming device being configured to be set an execution condition that defines a condition to execute the test print process, each image-forming device executing the test print process when the each image-forming device satisfies the execution condition; a first detecting unit that is configured to detect an execution condition of an image-forming device among the plurality of image-forming devices; and a setting unit that is configured to set an execution condition of an image-forming device among the plurality of image-forming devices based on the execution condition detected by the first detecting unit such that at least two execution conditions among execution conditions of the plurality of image-forming devices are different from each other.