If you want to download an image from https:
$output_filename = 'output.png';
$host = "https://.../source.png"; // <-- Source image url (FIX THIS)
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $host);
curl_setopt($ch, CURLOPT_VERBOSE, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_AUTOREFERER, false);
curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0); // <-- don't forget this
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0); // <-- and this
$result = curl_exec($ch);
curl_close($ch);
$fp = fopen($output_filename, 'wb');
fwrite($fp, $result);
fclose($fp);