I previously had 1.414 installed and was going to upgrade to later version 1.431. As of 1.414, I had been able to select specific images from subalbums to use in the parent album's thumbnail. Now only choices I see are random, most recent, first alphabetically, most viewed, oldest. Maybe I need a plugin or the setting has been moved? Is this feature no longer available?

Go to the gallery options tab and check the [i]show subalbum thumbs[/i] box. Remember that this feature can cause a bit of overhead since all the subalbums are searched and the images are listed (perhaps with their thumb image) in the drop-down.

Glad it was an easy fix! Thank you.