1. A blind-spot image display system for a vehicle, said blind-spot image display system comprising: a camera configured to capture surroundings of a vehicle, the surroundings being a blind spot from a driver; a monitor set at a location in a cabin of the vehicle; and an image processing controller configured to generate a monitor image signal for the monitor by image processing based on a real camera image signal inputted from the camera, the image processing controller including: a blind-spot image formation unit configured to perform point-of-view conversion on the real camera image signal inputted from the camera into a blind-spot image that is viewed from a position of the driver's point of view; a vehicle cabin image formation unit configured to form a vehicle cabin image that is viewed from the position of the driver's point of view; a see-through display image generation unit configured to render the vehicle cabin image to be superimposed on the blind-spot image into a semi-transparent vehicle cabin image; and an animation display image generation unit configured to generate an animation display image in which the vehicle cabin image to be superimposed on the blind-spot image is shifted stepwise from a non-transparent image to a see-through image; wherein said camera, said monitor, and said image processing controller are configured and interconnected such that, upon starting an animation display, the animation display image generation unit generates a display image for the monitor by image composition on the blind-spot image which is acquired based on the real camera image signal inputted from the camera, and the vehicle cabin image which is shifted from a non-transparent image at start to a semi-transparent image stepwise by adding a preset transparency to a transparency of the vehicle cabin image for every elapse of a preset time.