1. An image processing apparatus comprising: an operation unit that is to be operated by a user; a communication interface; an image processing engine; a memory storing a plurality of software; a controller configured to: in response to receiving a first start instruction for executing image processing based on a user's operation of the operation unit ( 12 ), execute association processing associated with the image processing by executing first software of the plurality of software; control the image processing engine to execute the image processing; execute load processing of loading predetermined data included in the first software by executing second software of the plurality of software, the predetermined data being for executing the association processing, the second software being different from the first software; in response to receiving a second start instruction of the image processing from an external apparatus via the communication interface, execute the association processing using the loaded predetermined data by executing the second software; and control the image processing engine to execute image processing.