diff --git a/epub.php b/epub.php
index 9464153..ddb36df 100644
--- a/epub.php
+++ b/epub.php
@@ -436,8 +436,15 @@
 		$doc = new DOMDocument();
 		$doc->loadHTML($issues);
 		$finder = new DomXPath($doc);
-		$cover = $finder->query('//img[contains(@src, "' . $issuenb . '_")]')->item(0)->getAttribute('src');
-		$epub->AddImage($cover, 'image/jpeg', true);
+		$cover = $finder->query('//img[contains(@src, "' . $issuenb . '_")]');
+		if ($cover->length)
+		{
+			$epub->AddImage($cover->item(0)->getAttribute('src'), 'image/jpeg', true);
+		}
+		else
+		{
+			echo 'warning: no cover for issue ' . $issuenb . '<br>';
+		}
 
 		// load feeds
 		$feed = file_get_contents($feedurl);