automatic sizing of vertical images

By inserting horizontal images of 1065*800 pixels, these are visible entirely on 1920*1080 or 1680*1050 desktop screens because the Content Area still has dimensions larger than the images themselves.
The same result is obtained with vertical images 600*800.
Reducing the screen size (for example to 1360*768), the horizontal images (1065*800) are automatically resized according to the width, so they fit on the screen even if you cannot see them in full because the new vertical size is slightly larger to the screen itself.
However, in the case of vertical images, automatic resizing does not occur because the width of the images (600) is much smaller than the screen (1360).
What parameter can I force or what code can I use to get vertical photos scaled by height instead of width, if that size is higher than the monitor size?