From command line with imagemagick, you can use:
convert dragon.gif -resize 64x64^ -gravity center -extent 64x64 fill_crop_dragon.gif
to resize and then crop an image so that it fills the area as much as possible.
How do I do this from Perl's Image::Magick?
#!/usr/bin/perl
use strict;
use warnings;
use Image::Magick;
my $image = Image::Magick->new;
$image->read('test.jpg');
$image->Set( Gravity => 'Center' );
$image->Resize( geometry => '64x64' );
$image->Extent( geometry => '64x64' );
$image->Write( 'test-out.jpg' );
See the PerlMagick documentation.