gistfile1.rb

def logo(options={})
  options.reverse_merge!({:category => "logo", :id => "logo", :alt => @store.branded_name, :link_title => @store.branded_name})
  return "" unless @store
  logo_img = ""  
  if logo_asset = @store.attachments.find_by_category(options[:category])
    logo_img += image_tag(logo_asset.url, {:id => options[:id], :alt => options[:alt]})
  elsif @store.logo?
    logo_img += image_tag(@store.logo.url, {:id => options[:id], :alt => options[:alt]})
  end
  controller.action_name.eql?('index') ? logo_img : link_to(logo_img, "/", :title => options[:link_title]) 
end

def header_img(category="header", id="header-img", alt=nil)
  if @store && header = @store.attachments.find_by_category(category)
    alt ||= header.alt_text
    image_tag(header.url, {:id => "header-img", :alt => alt})
  else
    return ""
  end    
end