An original monochrome image recorded with an FPD (flat panel detector) which comprises an array, m rows and n columns, of pixels is reduced and converted into a display image which comprises an array, q rows and (3*n*q/m) columns, of pixels before the display image is transferred to a monochrome liquid crystal display equipped with a monochrome LCD which comprises an array, q rows and P columns, of pixels, where m, n, q, and P are natural numbers and m≦n, q q are given. The monochrome liquid crystal display drives the three sub pixels of each pixel independently aligned along the row of the monochrome LCD to display the display image of the pixels in q rows and (3*n*q/m) columns.