An image forming apparatus and a method thereof has a printing log management function. An image forming apparatus allows a connection with an external memory device such as a mobile memory card, and prints out an image in accordance with the image data file which is stored in the external memory device. Among many files stored in the external memory device, the image forming apparatus memorizes and stores the information about the files which have been printed at least once, or specifically selected by a user. Accordingly, the user is enabled to print once-printed images or specific images without endeavoring cumbersome processes such as search or selection of a desired image data file. As a result, printing operations can be carried out faster and more efficiently.