1. An image forming apparatus comprising: a printing device that prints an image represented by image data onto a recording medium; at least one processor; and a memory storing computer readable instructions that when executed cause the image forming apparatus to perform the steps of: identifying an orientation of the image represented by the image data; identifying an orientation of the recording medium for use in printing by the printing device; determining if there is an inconsistency between the orientation of the image and the orientation of the recording medium; converting the image data, when there is inconsistency between the identified orientation of the image and the identified orientation of the recording medium, such that the orientations of the image and the recording medium are consistent with each other; and prohibiting conversion of the image data while allowing the printing to be performed in a current state when it is determined that there is an inconsistency between the orientation of the image and the orientation of the recording medium, under a predetermined condition, wherein when it is determined that there is inconsistency between the orientation of the image and the orientation of the recording medium, the image forming apparatus is configured to determine, based upon predetermined setting information, whether to perform printing in the current state, or whether to perform printing in a state in which the orientation of the image is consistent with the orientation of the recording medium, and then print the image in the current state, or in the state in which the orientation of the image is consistent with the orientation of the recording medium, in accordance with the setting information, wherein the memory stores computer readable instructions that when executed further cause the image forming apparatus to perform the step of: selecting whether to prohibit conversion of the image data while allowing the printing to be performed in the current state when it is determined that there is an inconsistency between the orientation of the image and the orientation of the recording medium; and the selection of whether or not to prohibit rotation of the image is performed based on previously set or stored information.