<?php

$filenames = array(
    '/Users/mbpro/Documents/bitbucket/brandpdf/storage/app/uploaded_pdfs/6ab4cc52-c4d4-44dd-9f65-a57eb77e142d/portrait-01.png',
    'Vacation (Me and Mom) (200.png',
    'Vacation (5) (3.png',
);

foreach ( $filenames as $filename ) {
    if ( preg_match( '/^.*\-(\d+)/s', $filename, $matches ) ) {
        echo "$filename => $matches[1]\n";
    } else {
        echo "$filename => no match!\n";
    }
}