This is the second time it happens. The site is running and suddenly, "No thumbnail" image appears for every thumbnail. If you try to see the picture, there is no picture (empty square with the red X in the upper left corner).
You can xheck it at http://www.fororodbuilding.com/pp/index.php
My las action as admin was 3 weeks ago.
How can I recover the pictures? How can I avoid this to happen in the future?.