<?php
$data = [
'f.pdf-0.jpg',
'f.pdf-1.jpg',
'f.pdf-10.jpg',
'f.pdf-11.jpg',
'f.pdf-12.jpg',
'f.pdf-19.jpg',
'f.pdf-2.jpg',
'f.pdf-20.jpg',
'f.pdf-3.jpg',
];
sort($data, SORT_NATURAL
);
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