Downloading 1000s of images using php , how to bypass blank images

Question

I have a php file that is creating a list of url paths of images i want to download. Currently i have just been creating a list , copying and pasting it in a desktop app that will download images by url list in txt file. I wanted to go ahead and add the download to the php file to bypass that current step.

currently the following generates a list of urls i use to copy and paste to desktop downloader app

foreach ($espn_ar as $key => $value) echo 'ht'.'tps://a.espncdn.com/i/headshots/nfl/players/full/'.$espn_ar[$key].'.png<br>';

the list that is generated looks like this , with approximately 2500 url paths

https://a.espncdn.com/i/headshots/nfl/players/full/2580.png
https://a.espncdn.com/i/headshots/nfl/players/full/2330.png
https://a.espncdn.com/i/headshots/nfl/players/full/2977742.png
https://a.espncdn.com/i/headshots/nfl/players/full/5528.png
https://a.espncdn.com/i/headshots/nfl/players/full/5529.png
https://a.espncdn.com/i/headshots/nfl/players/full/5536.png
https://a.espncdn.com/i/headshots/nfl/players/full/5713.png
https://a.espncdn.com/i/headshots/nfl/players/full/8439.png
https://a.espncdn.com/i/headshots/nfl/players/full/8461.png
https://a.espncdn.com/i/headshots/nfl/players/full/8479.png

To bypass the step of copying and pasting to a desktop app , i added the following

foreach ($espn_ar as $key => $value) {
    $url = 'ht' . 'tps://a.espncdn.com/i/headshots/nfl/players/full/' . $espn_ar[$key] . '.png';
    $img = 'images/' . $espn_ar[$key] . '.png';
    $ch = curl_init($url);
    $fp = fopen($img, 'wb');
    curl_setopt($ch, CURLOPT_FILE, $fp);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_exec($ch);
    curl_close($ch);
    fclose($fp);
}

This seems to be working to download all images into a directory setup called "images"

Question 1 - is what i have done the best method for what i'm trying to achieve ?

Question 2 - when using the desktop app it doesn't download a blank image if the url path doesn't contain an image, however using the php method it does download a blank image if one of the url paths doesn't contain any image, so how can i add something to not download a blank png file, or only download files over 1kb, or delete all files 1kb or smaller after all files downloaded, not sure what is best way to handle that.