--- loncom/cgi/plot.gif	2006/09/06 19:26:07	1.12
+++ loncom/cgi/plot.gif	2016/08/19 05:15:21	1.15
@@ -1,6 +1,6 @@
 #!/usr/bin/perl
 #
-# $Id: plot.gif,v 1.12 2006/09/06 19:26:07 albertel 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;
 
@@ -47,14 +48,19 @@ if ($output eq '') {
 }
 
 if ($output eq 'gif' || $output eq 'png') {
-    open PLOT, "gnuplot $filename |";
+    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
 
+$image_content
 END
-    while ($_=<PLOT>) {
-	print;
-    }
+
 } elsif ($output eq 'eps') {
     print <<"END";
 Content-type: text/html
@@ -65,7 +71,7 @@ Content-type: text/html
 
 END
     if (! system ("gnuplot $filename")) {
-        print "<h2>An error occured.</h2>\n".
+        print "<h2>An error occurred.</h2>\n".
             "I am not going to tell you about it as I have not bothered ".
             "to figure out how to get you the error text.\n";
     } else {