WordPress.com sites don’t allow users to import custom code into a blog post, so you will need to publish your blog posts differently.
Use Storytailor to create your blog then click Save. Once you’re happy with your blog post go to File > Export. Enter your blog width (times two, it will be 1600px or higher, remember Facebook requires 2048px to give you an idea on sizing).
Storytailor will then export row by row jepgs of the blog post that you created. Then, in WordPress, create a new blog post. Compose your text copy to your new blog post and then upload your JPG files. When ready, publish your blog post.