您可以发送HEAD请求allowed resources 直到你达到状态200, cache 结果（post meta、选项等），并显示最佳匹配。

允许的横幅大小和格式为：

\'banner-1544x500.png\',
\'banner-772x250.png\',
\'banner-1544x500.jpg\',
\'banner-772x250.jpg\',

允许的图标大小和格式：

\'icon.svg\',
\'icon-256x256.jpg\',
\'icon-128x128.png\',

发送HEAD请求可以通过使用wp_remote_head() 或者使用cURL。

让我们把它抽象出来：

namespace Wpse\\Http;

interface Remote_Resource
{
    /**
     * @param  string $url
     * @return bool
     */
    public function exists( $url );
}

final class Curl_Remote_Resource implements Remote_Resource
{
    /**
     * @param  string $url
     * @return bool
     */
    public function exists( $url )
    {
        $status = `curl -s -o /dev/null -I -w "%{http_code}" $url`;

        return 200 === (int) $status;
    }
}

现在，我们只需要一个类来针对不同的图像变化使用该检查：

/**
 * Find banners and icon for a plugin hosted on wordpress.org
 *
 *
 * @version 2015.08.09
 * @author  toscho
 * @license MIT
 */
final class Wp_Org_Assets
{
    /**
     * @see https://developer.wordpress.org/plugins/wordpress-org/plugin-assets/
     *
     * @var array
     */
    private $banners = [
        \'banner-1544x500.png\',
        \'banner-772x250.png\',
        \'banner-1544x500.jpg\',
        \'banner-772x250.jpg\',
    ];
    /**
     * @see https://developer.wordpress.org/plugins/wordpress-org/plugin-assets/
     *
     * @var array
     */
    private $icons = [
        // Do not embed unknown SVG in your HTML. Use the `<img>` element instead!
        \'icon.svg\',
        \'icon-256x256.jpg\',
        \'icon-128x128.png\',
    ];

    /**
     * @var string
     */
    private $url;

    /**
     * @var \\Wpse\\Http\\Remote_Resource
     */
    private $remote;

    /**
     * This constructor is private, use one of the static "named constructors" instead.
     *
     * @see http://verraes.net/2014/06/named-constructors-in-php/
     * @param string                     $slug Plugin slug like "multilingual-press"
     * @param \\Wpse\\Http\\Remote_Resource $remote
     */
    private function __construct( $slug, Remote_Resource $remote )
    {
        $this->url    = "https://plugins.svn.wordpress.org/$slug/assets";
        $this->remote = $remote;
    }

    /**
     * @param string                     $slug Plugin slug like "multilingual-press"
     * @param \\Wpse\\Http\\Remote_Resource $remote
     * @return static
     */
    public static function from_slug( $slug, Remote_Resource $remote )
    {
        return new static( $slug, $remote );
    }

    /**
     * @param string                     $url Plugin URL like "https://wordpress.org/plugins/multilingual-press/"
     * @param \\Wpse\\Http\\Remote_Resource $remote
     * @return static
     */
    public static function from_main_url( $url, Remote_Resource $remote )
    {
        $matches = [];
        preg_match( \'~/plugins/([^/]*)/~\', $url, $matches );

        return new static( $matches[ 1 ], $remote );
    }

    /**
     * @param string                     $url SVN URL like "https://plugins.svn.wordpress.org/multilingual-press/"
     * @param \\Wpse\\Http\\Remote_Resource $remote
     * @return static
     */
    public static function from_svn_url( $url, Remote_Resource $remote )
    {
        $matches = [];
        preg_match( \'~svn\\.wordpress\\.org/([^/]*)/~\', $url, $matches );

        return new static( $matches[ 1 ], $remote );
    }

    /**
     * @return string
     */
    public function banner()
    {
        return $this->find( $this->banners );
    }

    /**
     * @return string
     */
    public function icon()
    {
        return $this->find( $this->icons );
    }

    /**
     * @param array $list
     * @return string
     */
    private function find( array $list )
    {
        foreach ( $list as $file )
            if ( $this->remote->exists( "$this->url/$file" ) )
                return "$this->url/$file";

        return \'\';
    }
}

然后我们可以在几行代码中使用这些类：

$assets = Wp_Org_Assets::from_main_url( \'https://wordpress.org/plugins/multilingual-press/\', new Curl_Remote_Resource );
$files  = [
    \'banner\' => $assets->banner(),
    \'icon\'   => $assets->icon()
];

foreach ( $files as $name => $url )
{
    if ( $url )
        printf(
            \'%1$s: <a href="%2$s"><code>%2$s</code></a><br><img style="max-width: 100%%" src="%2$s"><br>\',
            $name,
            $url
        );
    else
        printf(
            \'No %s found.<br>\',
            $name
        );
}