This problem only came up recently for me, as of the latest update. Where my default program was set to Paintdotnet and the thumbnails were showing up. Now, they display the logo or icon, whichever it is. This is with new files that are either created or saved now. Reverting default to the Windows Photo Viewer changes it to the thumbnail, and then going back again to Paintdotnet keeps the thumbnail as it should be. Any solutions to this, or what?   Edit: I know that PDN is not suppose