Automatic scaling of the image when the window is resized is not going to be easy to do.

To refresh, setup a timer:

my $timer = Glib::Timeout->add (100,\&show_refresh);
# timer will run until callback returns false
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P.S. You don't need Mime::Base64 for a Gtk2 image.

To load an image from data try this (I load from a file, but it is converted to scalar data before using) :

#!/usr/bin/perl
use strict;
use warnings;
use Gtk2 '-init';

my $mw = Gtk2::Window->new;

my $vp = Gtk2::Viewport->new(undef, undef);
$mw->add($vp);

&load_image;

$mw->signal_connect('destroy', sub { Gtk2->main_quit });
Gtk2->main;

########################################################### 
sub load_image {

 my $file = shift || 'bridget-1.jpg';

my $image_data;
  open (FH,"< $file");
  read( FH, $image_data, -s FH );
  close FH;

 my $loader = Gtk2::Gdk::PixbufLoader->new;
  $loader->write ($image_data);
    $loader->close;
  my $pixbuf = $loader->get_pixbuf;

my $image = Gtk2::Image->new_from_pixbuf ($pixbuf);

my $pb = $image->get_pixbuf;
my ($x, $y) = ($pb->get_width, $pb->get_height);

$vp->add($image);

$mw->set_title("$file ${x}x${y}");
$mw->show_all();

}
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If you can deal with a temp file, there is a fantastic image viewer called Gtk2::ImageViwer. It has mouse zoom and pan, but it only loads from a file.

#!/usr/bin/perl
######################################################################
+ 
#  Trivial use of Dov Grobgeld's GtkImageViewer. 
######################################################################
+ 

use Gtk2;
use Gtk2::ImageViewer;

Gtk2->init;

$window = Gtk2::Window->new();
$window->signal_connect('destroy', sub { Gtk2->main_quit });

my $file = shift || 'bridget-1.jpg';

$imgv = new_from_file Gtk2::ImageViewer($file);
$window->add($imgv);

$window->show_all();

main Gtk2;
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