Check for retina version in PHP

Hi,

Is it possible to check for retina version of image in PHP?

I came up with something like this

function checkForRetinaVersion($url){
    $url_retina = str_lreplace(".", "@2x.", $url);
    $ch = curl_init($url_retina);
    curl_setopt($ch, CURLOPT_NOBODY, true);
    curl_exec($ch);
    $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);

    if($code == 200){
       return $url_retina;
    }else{
       return $url;
    }
    curl_close($ch);
}

But this would lead to lot of requests. Any better approach for that?

Thank you,

Philip

https://wordpress.org/plugins/wp-retina-2x/