[BUGFIX] Only replace the thumbnail with the youtube video

Resources/Public/JavaScript/youtubeLightbox.js

@@ -51,9 +51,10 @@ module.exports = function() {
 		$youtubeItem.css('display', 'block');
 
 		let queryString = prepareVideoUrl($youtubeItem.attr('href')),
-			width = $youtubeItem.outerWidth() + 'px',
-			height = $youtubeItem.outerHeight() + 'px';
-		$youtubeItem.replaceWith('<div class="sg-youtube-item sg-card-shadow" ' +
+			$thumbnailElement = $youtubeItem.find('.sg-youtube-image'),
+			width = $thumbnailElement.outerWidth() + 'px',
+			height = $thumbnailElement.outerHeight() + 'px';
+		$thumbnailElement.replaceWith('<div class="sg-youtube-item sg-card-shadow" ' +
 			'style="height: ' + height + '; width: ' + width + ';"><iframe ' +
 			'width="' + width + '" height="' + height + '" ' +
 			'src="https://www.youtube-nocookie.com/embed/' + queryString + '" frameborder="0" ' +