post_image.rb

class PostImage < ActiveRecord::Base
  # So we can code post_image.category instead of the uglier post_image.post_image_category
  belongs_to :category, :class_name => 'PostImageCategory', :foreign_key => 'post_image_category_id'
  
  # You may want to pass other options to has_attachment.
  # See the attachment_fu README.
  has_attachment :content_type => :image,
                 :storage => :file_system,
                 # There is no size restriction on thumbnails.
                 # But you'll probably want them to fit in the TinyMCE plugin popup dialog.
                 :thumbnails => {:small => '124'}
  validates_as_attachment
  named_scope :thumbnails, :conditions => {:thumbnail => 'thumbnail'}
end