Hi,
If anyone facing problem in displaying video thumb images, categories and playing videos after upgrade 2.7 version, download the latest package from http://wordpress.org/plugins/contus-video-gallery/ and replace the following files and folder.
\wp-content\plugins\contus-video-gallery\front (folder)
\wp-content\plugins\contus-video-gallery\ContusFeatureVideos.php
\wp-content\plugins\contus-video-gallery\ContusPopularVideos.php
\wp-content\plugins\contus-video-gallery\ContusRecentVideos.php
\wp-content\plugins\contus-video-gallery\ContusRelatedVideos.php
\wp-content\plugins\contus-video-gallery\myextractXML.php
\wp-content\plugins\contus-video-gallery\admin\controllers\videosettingsController.php
and remove \wp-content\plugins\contus-video-gallery\ContusFeaturedVideos.php file and check. If you are still facing any difficulties in this feel free to contact us.