Currently image_tag throws an error generating the alt attribute for images whose basename contains only periods.
Suggest simply casting possible nil to_s.
- options[:alt] ||= File.basename(options[:src], '.*').split('.').first.capitalize + options[:alt] ||= File.basename(options[:src], '.*').split('.').first.to_s.capitalize
Addressed in ticket 9018, patch at http://dev.rubyonrails.org/attachment/ticket/9018/9018_image_tag_alt_attribute_for_files_whose_basename_contains_only_periods.diff