$re = '/(?<=_V1_)(.+?)(?=.jpg)/';
$str = 'https://m.media-amazon.com/images/M/MV5BYWNlMWMxOWYtZWI0Mi00ZTg0LWEwZTMtZTEzZDY0NzAxYTA4XkEyXkFqcGdeQXVyMTQxNzMzNDI@._V1_UX182_CR0,0,182,268_AL_.jpg';
$subst = "";
$result = preg_replace($re, $subst, $str, 1);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php