opendir HTMLDIR, $directory_name or die "Can't open $directory_name: $!\n";
while (readdir (HTMLDIR)) {
	push @images, $_) if /\.(png|jpg|gif|tiff)/;
}

##</code><code>##

foreach ((readdir(HTMLDIR)) {
# stuff
}

##</code><code>##

my @files = grep { /png|gif|jpg|tiff$/ } (readdir(DIR));