--- loncom/cgi/plot.gif	2003/09/24 21:15:55	1.10
+++ loncom/cgi/plot.gif	2006/09/06 19:26:07	1.12
@@ -1,6 +1,6 @@
 #!/usr/bin/perl
 #
-# $Id: plot.gif,v 1.10 2003/09/24 21:15:55 matthew Exp $
+# $Id: plot.gif,v 1.12 2006/09/06 19:26:07 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -37,16 +37,19 @@ foreach (split/&/,$ENV{'QUERY_STRING'})
 my $filename = $data{'file'};
 # unescape filename
 $filename =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
-
 die if ($filename =~ /\// || $filename !~ /_plot.data$/);
 $filename = $tmpdir . $filename;
 die "$data{'file'} does not exist\n" if (! -e $filename);
 
 my $output = $data{'output'};
-if ($output eq 'gif') {
+if ($output eq '') {
+    $output = (split('\.',$0))[-1];
+}
+
+if ($output eq 'gif' || $output eq 'png') {
     open PLOT, "gnuplot $filename |";
     print <<"END";
-Content-type: image/gif
+Content-type: image/$output
 
 END
     while ($_=<PLOT>) {
@@ -72,6 +75,3 @@ END
 } else {
     die "output $output is not a recognized value or has no value\n";
 }
-
-
-