Determine the existence of remote images and capture them

$curl = curl_init();

<code>    curl_setopt($curl, CURLOPT_URL, $url);
    curl_setopt($curl, CURLOPT_HEADER, 0);
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);//关闭证书
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($curl, CURLOPT_TIMEOUT,8);
    $file = curl_exec($curl);
    curl_close($curl);</code>

When I make up an address randomly and the domain name exceeds 7 characters, for example: http://www.ffafffe.com/up358.jpg
The resulting $file is printed as:
string(686) "

Why, is there any solution

Reply content:

$curl = curl_init();

<code>    curl_setopt($curl, CURLOPT_URL, $url);
    curl_setopt($curl, CURLOPT_HEADER, 0);
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);//关闭证书
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($curl, CURLOPT_TIMEOUT,8);
    $file = curl_exec($curl);
    curl_close($curl);</code>

When I make up an address randomly and the domain name exceeds 7 characters, for example: http://www.ffafffe.com/up358.jpg
The resulting $file is printed as:
string(686) "

Why, is there any solution

Check the content-type of the response header. If it is image/*, it is basically an image. Some sites will return a default image to you, but this is another problem