1. An image processing device comprising: a processor; and a memory storing computer-readable instructions therein, the computer-readable instructions, when executed by the processor, causing the image processing device to perform: acquiring first image data representing a first image and second image data representing a second image, the first image including a first object image showing a part of a target object, the second image including a second object image showing another part of the target object, the first image including a first edge with respect to a first direction, the first object image including a first object-image edge with respect to the first direction, the first image including a plurality of first pixels located between the first edge and the first object-image edge, and the plurality of first pixels not being included in the first object image; selecting a first arrangement method when a specific condition is met, otherwise, selecting a second arrangement method when the specific condition is not met, the specific condition including a first condition indicating that the number of the plurality of the first pixels continuously arranged in the first direction is larger than a prescribed level; determining a relative position between the first image and the second image by using the selected one of the first arrangement method and the second arrangement method; and generating arranged image data representing an arranged image in which the first image and the second image are arranged according to the relative position so that the arranged image shows the target object.