Inserting image into post content - Front End

Question

This is the php I have for a form which creates a post with thumbnail. I want to know how to add the uploaded image to the post content as well. Tried a few things, but they didn't work.

 if(isset($_POST['new_post']) == '1') {

        $post_title = $_POST['post_title'];
        $post_category = $_POST['cat'];
        $filename = $_POST['attach'];

       $new_post = array(
          'ID' => '',
          'post_author' => $current_user->ID, 
          'post_category' => array($post_category),
          'post_title' => $post_title,
          'post_status' => 'draft'
        );

        $post_id = wp_insert_post($new_post);
        $post = get_post($post_id);
        $new_post = $post->ID;

     if (!function_exists('wp_generate_attachment_metadata')){
            require_once(ABSPATH . "wp-admin" . '/includes/image.php');
            require_once(ABSPATH . "wp-admin" . '/includes/file.php');
            require_once(ABSPATH . "wp-admin" . '/includes/media.php');
            }

             if ($_FILES) {
            foreach ($_FILES as $file => $array) {
                if ($_FILES[$file]['error'] !== UPLOAD_ERR_OK) {
                    return "upload error : " . $_FILES[$file]['error'];
                }
                $attach_id = media_handle_upload( $file, $new_post );
            }   
            }

            if ($attach_id > 0){

            //and if you want to set that image as Post  then use:
            update_post_meta($new_post,'_thumbnail_id',$attach_id);
            }

}

Answer 1

The content of the post is just that - the value of post_content field.

You could retrieve HTML for attachment by wp_get_attachment_image() and either pass it to wp_insert_post() initially (will need to create attachment earlier for that) or use wp_update_post() to assign content to already existing post.

Answer 2

The following code adds the image right at the beginning of your post. You can edit it in order to add the image wherever you need.

$get_post = get_post($new_post);
$post_content = $get_post->post_content;
$post_id = $getPost->ID;
$new_attach = wp_get_attachment_image($attach_id);
$post_content = $new_attach.$post_content;
$post_data = array('ID'=>$post_id,'post_content'=>$post_content);
wp_update_post($post_data);