I'm writing a Tk program to choose and copy photos choosing among hundreads of them.

It is almost complete and usable but when I've used it with a very big list of files i've noticed the program was eating my memory and finally become impossible to reproduce further images.

The original error generated was

      Tk::Error: not enough free memory for image buffer at [path]/lib/Tk/Image .pm line 21.

The original code that produced the above error is a bit complicated because i preload a number of photos to render them faster, it scale them to a customizable size (using modules), it handle rotation looking into EXIF tags..

So even if i was almost sure to had cleared all unneeded variables I decided to look at some classic author's example before claiming that Tk was eating my memory.

I've found Tk-thumbnail-viewer and i tried it loading seven pics of 3.5 Mb each one: the program occupy ~58Mb after had loaded thumbs and ~225Mb after i've clicked all 7 thumbs!

So I prepared a little test program reproducing the memory leak: on start it consumes ~7Mb but end at 7th photos with ~222Mb.

Looking at the process it seems sometimes it release some Mb of memory. Im working with Tk 804.032 on strawberry Perl 5.14.2

here the test program

#!/usr/bin/perl
use warnings;
use strict;

use Tk;
use Tk::JPEG;
use Tk::Pane;

use File::Spec;

use Data::Dump;

my $glob = $ARGV[0]||'./*.jpg';

my @files;
&build_list($glob);


###########################################################
my $mw = new MainWindow ();
   $mw->geometry("100x50+0+0");

$mw->Button(-text => "nex picture",
                  -command => sub{
                                  &next_pic;
                              }
                  )->pack();

my $phwin = $mw->Toplevel();

# default empty image
#  see http://www.perlmonks.org/?node_id=535837
my $image = $phwin->Photo(-file => '' ) or die $!;
my $photo_label;

#fill mainframe with default screen
setup_pane();

$mw->MainLoop;

######################################################################
+##########
sub next_pic {
   my $pic_file = shift @files;
   print "processing [$pic_file]\n";

   $image->blank;
   $image = $phwin->Photo(-file => $pic_file );

   $photo_label->configure(-image => $image );

}
#############################################################
# see http://www.perlmonks.org/?node_id=535837
sub setup_pane{

  my $pane = $phwin->Scrolled('Pane', Name => 'Main Display',
               -width => 1000,
               -height =>1000,
               -background => 'black',
               -scrollbars => 'osoe',
               -sticky => 'n',
              )->pack(-side => "left", -anchor => "n",
                      -fill=>'both',-expand=>1);

  # the global!
  $photo_label = $pane->Label(-image => $image,
                      -background =>'black'
                     )->pack(-side => 'top',
                       -anchor => 'n',
                       -fill => 'both',
                       -expand => 1,
                      );

}
######################################################################
+##########
sub build_list{
    my $glob=shift;
    print "received [$glob]\n";
    map {
          push @files,File::Spec->file_name_is_absolute($_) ?
                        $_ : File::Spec->rel2abs($_);
    } glob($glob);
    print "$_\n" for @files;
}
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How can i inspect the memory used by the program?

How can i prevent memory usage increase while cycling my photos?

I'm missing some Tk related best practice?

L*