<p>Hello,For each theme the following files/folders are created:- a folder with the theme name. In the folder is a xml-file and if the theme has an image background then the background image is located there as well.- a thumbnail in the thumbnails folder- a preview image of the theme in the theme root folder (the folder in which the other theme folder are)When the preview image is not there, then OpenLP will not recognise the theme. So just copy the thumbnails in the theme root folder. And start OpenLP, that should fix your problem. However, the preview images here have a resolution of 800x600. When you copy the thumbnails the resolution is just 117x88. To ensure that the resolution of the preview images is correct you have to "edit" each theme (so that the preview image is recreated with the correct resolution).Regards</p>