Create a page resource and attach an uploaded image View the page and open the URL of the image, URL will be something like this: http://example.com/pluginfile.php/12464/mod_page/content/1/Main%20page%20image.jpg add ?preview=bigthumb to the end of the image URL make sure the thumbnail is generated and there is no white line on the right Try with other images that have vertical layout P.S. If you had already tested it before on the same instance with the same image, you need to delete generated preview files DELETE FROM mdl_files WHERE component='core' and filearea='preview'