#!/usr/bin/perl
use warnings;
use strict;
use Image::Magick;

my $filename = shift;
my $target   = $filename;
   $target =~ s/(\..*$)/_thumb$1/;

my $image = new Image::Magick;

$image->Read( $filename );
my ($width, $height) = $image->get('width', 'height');

if ( $width > $height ) {
    my $diff = $width - $height;
    $width -= $diff;
    my $xoffset = ( $diff / 2 );
    $image->Crop( geometry => "${width}x$height+$xoffset+0" );
}
else {
    my $diff = $height - $width;
    $height -= $diff;
    my $yoffset = ( $diff / 2 );
    $image->Crop( geometry => "${width}x$height+0+$yoffset" );
}

$image->Scale( width => 100, height => 100 );
$image->Write( $target );