Another problem I found is that in some cases a thumb directory exists for an image, but no thumbs exist in that directory, and no primary image exists either. This works to generate rendering errors in pages as seen below:

Error creating thumbnail: convert: unable to open image `/var/www/wiki/images/f/f0/Soviet_Electric_grid_82.jpg': No such file or directory. convert: missing an image filename `/var/www/wiki/images/thumb/f/f0/Soviet_Electric_grid_82.jpg/300px-Soviet_Electric_grid_82.jpg'. Map of the electric grid during the Soviet era.

Is there a fix for this? Obvious having an update to image database would be effecient, but in lieu of that, a fix?