Regarding the use of equal ids, keep in mind that ids are a way of identifying an element, and must be SINGLE for each element, so use classes that are a way of identifying a group of elements.
$htmlImagens =<<<DEMO
<img src="/images/blog/outra-imagem-A.jpg" />
<img class="img_blog" src="/images/blog/outra-imagem-B.jpg" />
<img class="img_blog" src="/images/blog/cliente-ideal-voce-sabe-quem-e.jpg" />
<img src="/images/blog/outra-imagem-C.jpg" />
<img src="/images/blog/outra-imagem-D.jpg" />
DEMO;
$dom = new DOMDocument();
$dom->loadHTML($htmlImagens);
//fazemos um loop procurando por ocorrências da Tag “img”
foreach($dom->getElementsByTagName('img') as $image) {
//destacamos somente aquelas com classe "img_blog"
if(strstr($image->getAttribute('class'),'img_blog')==true){
// o array com os src das tags img cuja classe é "img_blog"
$images[] = $image->getAttribute('src');
}
}
print_r($images);
See working at repl.it
Bibliography
DOMDocument
foreach
strstr