Landscape images on home screen don't match actual image of media item.

[nothingveryobvious]

I have a library of "Home Movies" and for some of the items, on the home screen there is either the wrong image (from an anime or something else) or no image at all for the item, but when I click on the item it shows the normal, expected image (a screengrab).

Here is what it looks like for an item on the home screen.


Here is what it looks like when I click on the actual item.


What can I do about this? Any help would be greatly appreciated. Thank you!