use strict;
use warnings;
use Image::Magick;

my $image = Image::Magick->new();
my $x = $image->Read('tail0.jpg', 'tail1.jpg', 'tail2.jpg', 'tail3.jpg');

$x = $image->Append(stack => 0); # horizontal
#$x = $image->Append(stack => 1);  # vertikal

$x->Write('tails.jpg');