An image forming apparatus capable of providing security for print right-associated image data. An image forming apparatus is capable of communicating with a management server that manages print rights. When printing image data stored in the storage section, a CPU determines whether a print right is associated with the image data. Whenever it is determined that a print right is associated with image data, the CPU makes an inquiry of the management server about print permission of the image data associated with the print right. A printer section prints an image represented by the image data when a response from the management server indicates that the image data associated with the print right is permitted to be printed.