Add thumbnail_input method to support form builder

Just to clean up this relatively common input type!

app/helpers/support_form_helper.rb

@@ -1,7 +1,7 @@
 module SupportFormHelper
 	class SupportFormBuilder < ActionView::Helpers::FormBuilder
 		attr_reader :template
-		delegate :concat, :content_tag, to: :template, private: true
+		delegate :concat, :content_tag, :image_tag, to: :template, private: true
 
 		def fields(&block)
 			content_tag(:ul, class: "fields", &block)
@@ -30,6 +30,14 @@ module SupportFormHelper
 		def radio_grid_fieldset(*args, &block)
 			radio_fieldset(*args, "data-type": "radio-grid", &block)
 		end
+
+		def thumbnail_input(method)
+			url = object.send(method)
+			content_tag(:div, class: "thumbnail-input") do
+				concat image_tag(url, alt: "Thumbnail") if url.present?
+				concat url_field(method)
+			end
+		end
 	end
 
 	def support_form_with(**kwargs, &block)

app/views/alt_styles/edit.html.haml

@@ -29,10 +29,7 @@
 
 		= f.field do
 			= f.label :thumbnail_url, "Thumbnail"
-			.thumbnail-input
+			= f.thumbnail_input :thumbnail_url
-				- if @alt_style.thumbnail_url?
-					= image_tag @alt_style.thumbnail_url
-				= f.url_field :thumbnail_url
 
 	.actions
 		= f.submit "Save changes"

app/views/items/edit.html.haml

@@ -23,10 +23,7 @@
 
 		= f.field do
 			= f.label :thumbnail_url, "Thumbnail"
-			.thumbnail-input
+			= f.thumbnail_input :thumbnail_url
-				- if @item.thumbnail_url?
-					= image_tag @item.thumbnail_url
-				= f.url_field :thumbnail_url
 
 		= f.field do
 			= f.label :description