diff --git a/ext/rss_images/main.php b/ext/rss_images/main.php
index 55bad355..3120e498 100644
--- a/ext/rss_images/main.php
+++ b/ext/rss_images/main.php
@@ -49,7 +49,7 @@ class RSS_Images extends Extension {
 			$image_url = $image->get_image_link();
 			$posted = date(DATE_RSS, $image->posted_timestamp);
 			$content = html_escape(
-				"<p>" . Themelet::build_thumb_html($image) . "</p>" .
+				"<p>" . $this->theme->build_thumb_html($image) . "</p>" .
 				"<p>Uploaded by " . html_escape($owner->name) . "</p>"
 			);
 
diff --git a/ext/rss_images/theme.php b/ext/rss_images/theme.php
new file mode 100644
index 00000000..d1f2734f
--- /dev/null
+++ b/ext/rss_images/theme.php
@@ -0,0 +1,4 @@
+<?php
+/* needed for access to build_thumb_html */
+class RSS_ImagesTheme extends Themelet {}
+?>