1. An image processing device comprising: a processor; and a memory storing computer-readable instructions that, when executed by the processor, implement: an image acquisition section that acquires an image that has been acquired by imaging a tissue using an endoscope apparatus; an in vivo position and moving distance identification information acquisition section that acquires, based on the acquired image: (a) in vivo position identification information that specifies an in vivo position of the endoscope apparatus when the image has been acquired; and (b) moving distance information that indicates an in vivo moving distance of the endoscope apparatus; an in vivo model acquisition section that acquires an in vivo model that schematically represents a model of the tissue; an on-model position determination section that specifies an on-model position that corresponds to the position specified by the in vivo position identification information on the acquired in vivo model; and a linking section that links information about the acquired image to the specified on-model position; wherein the in vivo position and moving distance identification information acquisition section includes a correction section that corrects the moving distance information based on structural properties of the entirety or part of a tissue where the endoscope apparatus has moved; and wherein the on-model position determination section specifies the on-model position that corresponds to the acquired image based on the moving distance information corrected by the correction section.