--- loncom/cgi/plot.gif	2013/08/14 00:38:55	1.14
+++ loncom/cgi/plot.gif	2016/08/19 05:15:21	1.15
@@ -1,6 +1,6 @@
 #!/usr/bin/perl
 #
-# $Id: plot.gif,v 1.14 2013/08/14 00:38:55 raeburn Exp $
+# $Id: plot.gif,v 1.15 2016/08/19 05:15:21 musolffc Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -25,6 +25,7 @@
 # http://www.lon-capa.org/
 #
 use strict;
+use bytes;
 
 $|=1;
 
@@ -48,14 +49,17 @@ if ($output eq '') {
 
 if ($output eq 'gif' || $output eq 'png') {
     open(my $plot, "gnuplot $filename |");
-
+    my $image_content= '';
+    while (my $line = <$plot>) {
+        $image_content .= $line;
+    }
+    my $length = bytes::length($image_content);
     print <<"END";
 Content-type: image/$output
+Content-length: $length
 
+$image_content
 END
-    while (my $line = <$plot>) {
-	print($line);
-    }
 
 } elsif ($output eq 'eps') {
     print <<"END";