app/assets/javascripts/adminpanel/sections.js.coffee
$(document).on 'click', 'a.add-fields', ->
# add image on sections form
$collectionContainer = $(@).closest('.file-collection-container')
maxFiles = $collectionContainer.data('max')
numberOfFiles = $collectionContainer.find('.product-image:not(.hidden)').length + 1
if maxFiles != 0 && numberOfFiles > maxFiles
$(@).addClass('hidden')
$(document).on 'click', '.btn.btn-danger.remove-fields', ->
# remove image on sectiosn form
$('a.add-fields').removeClass 'hidden'