Choose collage layout on multiple picture posts

Id love to be able to choose the layout of my pictures. For example, now if you do three pictures in one post, itll show as two small thumbnails above and one large below. Itd be neat if they could all be large and stacked on top one another for example! I often find myself wanting this when posting two pictures in one post. Of course thered then need to be lot of variables to choose from. Thank you for your consideration!