How can I add a background image to an input in a simple_form_for - Rails

I'm creating simple form in rails for create a new account, each account must has their icon. but I don't know how can I use the icon association to add in the input_html their respective icon image.

I'm trying to display the list of icons, the Icons has an url and their has a foreign key in the accounts, so I'm using this:

<%= simple_form_for [@account], data: { account_card_target: "form" } do |f| %>
        <div class="form-inputs">
          <%= f.input :account_name %>
          <%= f.input :account_type,
                      collection: ['***', '***', '***', '***'],
                      prompt: "Select a type" %>
          <%= f.input :balance %>
          <%= f.input :account_number  %>
          <%= f.association :icon,
                as: :radio_buttons,
                label_method: ->(icon) { "<label class='icon-radio-label' for='my-input' style='background-image: url(#{cl_image_path(icon.url)})'></label>".html_safe },
                value_method: :id,
                input_html: { class: 'my-input', id: 'my-input' }
        %>
        </div>
        <div class="form-actions">
          <%= f.button :submit %>
        </div>
<% end %>

but in this code I'm adding the background to the label, and I wanna have the label empty and use the background image in the input.

If I use this I can add the bg image to the imput but i don't know how can I replace the 'saving_icon' for the icon.url, because I alerady try with lambda but still not working

<%= f.association :icon,
        as: :radio_buttons,
        label_method: ->(icon) { " " },
        value_method: :id,
        input_html: {
          class: "icon-radio",
          style: "background-image: url(#{cl_image_path('saving_icon')});"
        }
%>

any tip for achive this it'll be well received, thank you!