diff --git a/theme/flexslider.theme.inc b/theme/flexslider.theme.inc
index c3b27d4..4e83798 100755
--- a/theme/flexslider.theme.inc
+++ b/theme/flexslider.theme.inc
@@ -140,6 +140,11 @@ function template_process_flexslider_list_item(&$vars) {
     preg_match("<img.+?src=[\"'](.+?)[\"'].+?>", $item, $src);
 
     if (!empty($src[1])) {
+      // Correct for image style, so that the thumbnail image style as defined
+      // in the optionsset is used, instead of the normal image style.
+      if ($settings['optionset']->imagestyle_thumbnail) {
+        $src[1] = str_replace($settings['optionset']->imagestyle_normal, $settings['optionset']->imagestyle_thumbnail, $src[1]);
+      }
       $attributes['data-thumb'] = $src[1];
     }
   }