$username = "ZX";
$password = "ZX";
$host = 'http://ZX.com/wp-json/wp/v2/media';
$data = json_encode($data);
$file = '/Users/xx.png';
$imagedata  = file_get_contents($file);
$process = curl_init($host);
curl_setopt($process, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($process, CURLOPT_BINARYTRANSFER, TRUE);
curl_setopt($process, CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($process, CURLOPT_TIMEOUT, 50);
curl_setopt($process, CURLOPT_USERPWD, $username . ":" . $password);
curl_setopt($process, CURLOPT_POSTFIELDS, $data);
curl_setopt($process, CURLOPT_HTTPHEADER, array('Content-Type:image/png','Content-Disposition:attachment;filename='.$file));
$return = curl_exec($process);
print_r($return);

$data = array(
  "status" => "draft",
  "title" => "Photo media",
  "description" => "Photo media1",
  "media_type" => "image",
  "alt_text" => "alternate text"
  );

$media = media_sideload_image(
    'http://i.imgur.com/bcJvAj0.jpg',
    $post->ID,
    'Some image description',
    'src'
);

if ( ! empty( $media ) and ! is_wp_error( $media ) ) {
    // reference new image to set as featured
    $attachments = get_posts( [
        'post_type'      => 'attachment',
        'posts_per_page' => 1,
        'post_status'    => 'any',
        'post_parent'    => $post->ID,
    ] );

    if ( is_array( $attachments ) ) {
        set_post_thumbnail( $post->ID, $attachments[0]->ID );
    }

    // Test print our image. The return value is the src of the sideloaded image.
    printf( '<img src="%s" />', $media );
}