1. An image forming method, comprising: displaying a plurality of operations applicable to an image data; selecting, from the plurality of operations, an operation including one or more sub-operations to be added to at least one previously selected operation which is to be applied to the image data; adding the selected operation to the at least one previously selected operation; displaying for additional selection, in response to the selection of the operation to be added to the at least one previously selected operation, only the one or more sub-operations which are determined as being executable in association with the selected operation, and selecting one sub-operation from the one or more sub-operations; setting an order in which the selected one sub-operation of the selected operation is to be executed upon the image data; setting detailed setup information for the selected one sub-operation of the selected operation; executing upon the image data, in the set order, the selected one sub-operation of the selected operation; and triggering storage of the set order of the selected one sub-operation of the selected operation and the detailed setup information for the selected one sub-operation of the selected operation after executing the selected one sub-operation of the selected operation.