The preview of the customized video slideshow (aka Ken Burns effect) looks different than it does on the actual tour. Why?
The preview is only an approximation of what you'll see since the player's aspect ratio cannot be predicted in advance. Since the way the image looks in the player depends on not only the custom rectangle you've set up, but also the aspect ratio of the image and the aspect ratio of the player. It also depends on our "snap to fill" setting which will zoom the image by about 30% to avoid letterboxing of the image.
Presently the snap to fill setting is not customizable, though we may allow it in the future.
The bottom line is that the preview is just an approximation, so don't expect it to or depend on it to look exactly the same in the player.