Provided is an image data transmitting apparatus capable of transmitting an image data in a given form according to a command from the receiving side. The image data transmitting apparatus is an image data transmitting apparatus transmitting image data to a receiving apparatus through a network, and includes: image data converting unit not only converting the image data to a converted image data file but also preparing file information of the converted image data file; posting unit posting the file information to the receiving apparatus; receiving unit receiving command information concerning a transmitting method for the converted image data file; and transmission controlling unit transmitting the converted image data file to the receiving apparatus based on the command information.