edit.html.erb

<div class="text-center">
    <%= image_tag @post.image.url(:medium) %>
</div>
<div class="form-wrapper">
    <%= simple_form_for @post, html: { class: 'form-horizontal', multipart: true } do |f| %>
        <div class="form-group">
            <%= f.input :image %>
        </div>
        <div class="form-group text-center">
            <%= f.input :caption %>
        </div>
        <div class="form-group text-center">
            <%= f.button :submit, class: 'btn-success' %>
        </div>
    <% end %>
</div>
<div class="text-center edit-links">
    <%= link_to "Delete Post", post_path(@post), method: :delete, data: { confirm: "Are you sure you want to delete this post?" } %> |
    <%= link_to "cancel", posts_path %>
</div>