my $data = 'yada...yada...yada..
<img src="111">
yada...yada...yada..
<img src="222">
yada...yada...yada..
<h1>Some title</h1>
yada...yada...yada..
<a href="444444">
<img src="333">
yada...yada...yada..
<img src="444">';

my $dom = Mojo::DOM->new($data);
for my $img ( $dom->find(q{h1 ~ img})->each )
        {
         print $img->attr(q{src});
        }