1. An image display device for displaying a first image on a screen including first and second regions different from each other, the image display device comprising: a sensor position detecting unit that detects a position on a screen where an image sensor is provided, the position corresponding to the first region hidden by the image sensor; and an image processing unit that: specifies the second region being contiguous with the position on the screen where the image sensor is provided; by computing a difference between a total display region and the first region, calculates an image size of the second region; computes an image size of the calculated second region and an image size of the first region, and generates a new image that reduces an obtained total image size to become the image size of the second region; and displays the new image at the second region.