你可以编写一个php脚本，或者在这里为这段代码制作你自己的插件，我在我的一个项目中使用了它，在那里我必须导入大量图像。

首先，获取图像，并将其存储在上载目录中：

$uploaddir = wp_upload_dir();
$uploadfile = $uploaddir[\'path\'] . \'/\' . $filename;

$contents= file_get_contents(\'http://mydomain.com/folder/image.jpg\');
$savefile = fopen($uploadfile, \'w\');
fwrite($savefile, $contents);
fclose($savefile);

$wp_filetype = wp_check_filetype(basename($filename), null );

$attachment = array(
    \'post_mime_type\' => $wp_filetype[\'type\'],
    \'post_title\' => $filename,
    \'post_content\' => \'\',
    \'post_status\' => \'inherit\'
);

$attach_id = wp_insert_attachment( $attachment, $uploadfile );

$imagenew = get_post( $attach_id );
$fullsizepath = get_attached_file( $imagenew->ID );
$attach_data = wp_generate_attachment_metadata( $attach_id, $fullsizepath );
wp_update_attachment_metadata( $attach_id, $attach_data );

您可以使用这些功能download_url() 和wp_handle_sideload().

download_url()

wp_handle_sideload()

示例：

// Gives us access to the download_url() and wp_handle_sideload() functions
require_once( ABSPATH . \'wp-admin/includes/file.php\' );

// URL to the WordPress logo
$url = \'http://s.w.org/style/images/wp-header-logo.png\';
$timeout_seconds = 5;

// Download file to temp dir
$temp_file = download_url( $url, $timeout_seconds );

if ( !is_wp_error( $temp_file ) ) {

    // Array based on $_FILE as seen in PHP file uploads
    $file = array(
        \'name\'     => basename($url), // ex: wp-header-logo.png
        \'type\'     => \'image/png\',
        \'tmp_name\' => $temp_file,
        \'error\'    => 0,
        \'size\'     => filesize($temp_file),
    );

    $overrides = array(
        // Tells WordPress to not look for the POST form
        // fields that would normally be present as
        // we downloaded the file from a remote server, so there
        // will be no form fields
        // Default is true
        \'test_form\' => false,

        // Setting this to false lets WordPress allow empty files, not recommended
        // Default is true
        \'test_size\' => true,
    );

    // Move the temporary file into the uploads directory
    $results = wp_handle_sideload( $file, $overrides );

    if ( !empty( $results[\'error\'] ) ) {
        // Insert any error handling here
    } else {

        $filename  = $results[\'file\']; // Full path to the file
        $local_url = $results[\'url\'];  // URL to the file in the uploads dir
        $type      = $results[\'type\']; // MIME type of the file

        // Perform any actions here based in the above results
    }

}

将远程图像导入WordPress至少有三种方法：

1. Grab and Save Plugin, 另一个答案中提到了这一点。此插件有点旧，它直接保存文件，因此不会创建不同大小的缩略图。上一次更新是在2年前撰写本文时。

2. Import External Image Plugin 具有远程链接图像的大容量导入。您可能需要增加PHP内存限制才能正常工作。上一次更新是在2年前撰写本文时。

3. Save & Import Image from URL Plugin 使用本机函数导入图像，以便在媒体库中正确创建图像，并生成所有缩略图等。该插件最近一次更新是在2016年，可与WordPress 4.7配合使用

   披露：我创建了Save & Import Image from URL Plugin