logic made nicer

app/controllers/packages_controller.rb

@@ -296,15 +296,21 @@ class PackagesController < ApplicationController
     end
 
     # Return a 404 if the package has no screenshots or the image was not found
-    unless @image
+    if @image
+      send_file(File.join(@image.simage.storage.directory, @image.simage(size).id),
+                disposition: 'inline')
+    else
       Rails.logger.debug 'no such image -> 404'
-      screenshot404 if %i[large small].include?(size)
+      case size
-      thumbnail404 if size == :thumb
+      when :large
-      return
+        screenshot404
+      when :small
+        screenshot404
+      when :thumb
+        Rails.logger.debug 'thumb404'
+        thumbnail404
+      end
     end
-
-    send_file(File.join(@image.simage.storage.directory, @image.simage(size).id),
-              disposition: 'inline')
   end
 
   # Receives a form with a simple text field 'description' so that users can update