Maybe something like this will help (it is a piece of code that I recently wrote for my weblog to accept entries via email):

#!/usr/bin/perl -w
use strict;

use MIME::Parser;
use FileHandle;
use File::Path;

$|++; # autoflush on

# Directory paths 
my $tmp_dir = '/home/moxliukas/tmp';
my $output_dir = '/home/moxliukas/public_html/moblog/images';

my $parser = MIME::Parser->new;
$parser->output_dir($tmp_dir);
my $entry = $parser->parse(\*STDIN);

# for each MIME message part...
for my $part ($entry->parts) {
      # ...check MIME type
        my $mime = $part->mime_type;
        if($mime =~ /jpeg/) {
                # if it is JPG, generate a new filename
                my $url = time() . '.jpg';
                my $fh = FileHandle->new($output_dir . '/' . $url, 'w'
+);
                binmode($fh);
                # Let's write the JPG to the output directory
                my $ifh = $part->open('r');
                $fh->print($ifh->getlines);
                $_->close for($fh, $ifh);
}
$dbh->disconnect;
[download]

Hope this helps.