Why do images look cropped in videos?

Wondering why images displayed in Video Slideshows appear to crop out the top and bottom of the image?

16:9 aspect ratio

It's because videos are displayed at a 16:9 aspect ratio, in other words - a thinner rectangle that a property photo so some of the image will be cropped out. Here's how a typical video looks...

This shows the different aspect ratios on a photo vs a video...

Landscape images

The crop is not too bad on images in landscape orientation, just a little off the top and bottom...

Portrait images

The crop on portrait images, however, is very significant, for this reason it's not possible to use them in Video Slideshows...