Rails 4, simple form, accepts_nested_attributes_for, upload a Dropzone image

Question

Rails 4, simple form, accepts_nested_attributes_for, upload a Dropzone image

Is there a way with the has_many association (User → Uploads) to work with a nested form? My strong parameters work fine. Users can upload 5 images. I am using accepts_nested_attributes_for in the model and loading works, but there are some gotchas.

But, for example, when I try to edit a user and create only new images using:

(5 - @user.uploads.count).times { @user.uploads.build }

... he builds 5 loadable records inside a nested form, no matter what. The form section is as follows:

<%= f.simple_fields_for :uploads do |i| %>
      <hr>
      <% user.uploads.each do |upload| %>
        <% if upload.image? %>
          <%= image_tag(upload.image.url(:medium), class: 'img-rounded').html_safe %>
          <br>
          <%= i.input :_destroy, as: :boolean,
                              label: false,
                       inline_label: 'Remove picture',
                       wrapper_html: { class: 'text-center' } %>
        <% end %>
      <% end %>

        <%= i.file_field :image %>
        <h4>or</h4>
        <%= i.input :image_remote_url, label: 'Enter an image URL' %>
    <% end %>