[Kib]

Seriously, a lot of talk here.

To answer the question: this is simply a skinning issue and can be coded quite easily in the skin.

I have been thinking of implementing this for Neon in the past, as it annoyed my girlfriend at some point in the past when she was watching Masterchef and the thumbnail of a recently added episode (final) showed her the winner.

As a suggestion: check out how the skin decides whether or not to show the plot (there is a view condition that shows when the watched state is 0) and how some skins decide to show either a full or small plot (skin setting off shows full plot, skin setting on shows small plot).
You could duplicate the thumbnail object and use similar conditions to either show the full thumb or the fallback thumb.

If I happen to have time I might code this in Neon, and then you could either start using that skin or base your own modifications for your favourite skin on it. This seems quite unlikely to happen in the next months as I have little time, and skinning is on the lowest of my priorities.