The way Gtk2's graphics subsystem is setup, a c lib, like libgeotiff, will make itself available to the pixbufloader. So once you install it, the format should be available for display. Getting the meta-data out may take an additional step. Maybe ask on the Perl/Gtk2 maillist.

#!/usr/bin/perl
use strict;
use warnings;
use Gtk2;


my @formats = Gtk2::Gdk::Pixbuf->get_formats();

my @exts;

foreach my $format ( @formats ) {
    foreach my $key ( keys( %$format ) ) {
           next unless $key eq 'extensions';  
         
       foreach my $elem ( @{ $format->{ $key } } ) {
                push @exts, $elem;
            }
        
     } 
 }
print "@exts\n";
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or

#!/usr/bin/perl
use strict;
use warnings;
use YAML;
use Gtk2;

my (@formats) =  Gtk2::Gdk::Pixbuf->get_formats;
print Dump([\@formats]);
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