An image processing apparatus enables a user to widely select a desired transfer method, in relation to methods of transferring image data to be output to a transfer destination. To accomplish this, the image processing apparatus allows the user to set instruction information for instructing a transfer method of image data, and decides on a transfer method based on the set instruction information if the image data is color data. This transfer method includes a first transfer method of transferring color image data, a second transfer method of converting color image data to monochrome image data and transferring the monochrome image data, and a third transfer method of storing color image data in a storage unit and transmitting a report showing that image data has been received to a transfer destination printer.