Dropdown on details page allows image management for users and admins

app/controllers/packages_controller.rb

@@ -90,6 +90,15 @@ class PackagesController < ApplicationController
     send_file @screenshot.image.path(:thumb), type: "image/png", disposition: 'inline'
   end
 
+  # Receives a form with a simple text field 'description' so that users can update
+  # the description of their screenshot.
+  def update_screenshot_description
+    @screenshot = Screenshot.find(params[:id])
+    @screenshot.description = params[:description]
+    @screenshot.save!
+    redirect_to package_path
+  end
+
   private
 
   # Send a dummy thumbnail reading "No screenshot available. Sorry."