diff --git a/ext/zoom/theme.php b/ext/zoom/theme.php
index 76819d67..4815cf36 100644
--- a/ext/zoom/theme.php
+++ b/ext/zoom/theme.php
@@ -29,7 +29,7 @@ function scale(img) {
 			msg_div.style.display = "block";
 		}
 		else {
-			img.style.width = orig_width;
+			img.style.width = orig_width + 'px';
 			msg_div.style.display = "none";
 		}
 	}