According to one embodiment, a vehicle-mounted monitor display system includes a camera which captures an image of outside scenery which is a blind spot of a driver created by a pillar, a display which displays an image on the pillar, and an image processing device which generates a display image by cutting out the image captured by the camera in conformity with a display range of the pillar, and outputs the display image to the display. In the image processing device, a resolution of the display image is reduced in a state where a vehicle equipped therewith is moving.