We have many chances to watch stereoscopic images, i.e., 3D movies and 3D TV programs. However, there has been little focus on the relationship between screen size and viewing distance with regards to stereoscopic images. We explain a subjective evaluation of the preferable viewing distance (PVD) and minimum viewing distance (MVD) for both still and moving images of different sizes, including monoscopic and stereoscopic images with different displarity maps. The results indicate that (1) for both the PVD and the MVD, the people stood closer to the images relatively as the image sizes became larger in terms of absloute display height, (2) for smaller image sizes, people stood farer to the stereoscopic images than monoscopic images, either the PVD and the MVD, and (3) differences in the disparity map in stereoscopic images do not affect the viewing distance in either still or moving images. These results may provide a guide to visual environmental design of larger stereoscopic display systems.