Yes, you can add multiple images, but you must select a multi-image card template (on mobile / computer board), or add extra images to the design editor (this is only possible on a PC or laptop). You can also choose a template from our "Create your own" option available under each category and add and position your images and your text as you wish.
Also, keep in mind that if you customize an existing template, we cannot change its pervasive design, e.g. insert or remove decorative picture frames.