[...]

my %attachments;
for (@imgfiles) {
  $attachments{$_} = {
    _disptype => 'GIF Image',
    _inline => $_,
    description => 'ATM-Image',
    ctype => 'image/gif',
    file => $imgdirfiles
  };
}

email({
  from => 'alice@example.com',
  to => 'bob@example.com',
  [...]
  _attachments => \%attachments
}) or die "sending mail failed: $@";

[...]