relying on ActionView's helper methods to construct the HTML

lib/zoomifier_helper.rb

@@ -2,7 +2,9 @@ module Zoomifier
   module ViewHelpers
     def zoomify_image_tag(source, options = {})
       raise ArgumentError unless options[:id]
-      "<div id=\"#{options[:id]}\"><img src=\"#{source}\" alt=\"\"/></div>"
+      content_tag :div, { :id => options[:id] } do
+        image_tag source, options.merge({ :id => nil })
+      end
     end
   end
 end

spec/zoomifier_helper_spec.rb

@@ -16,7 +16,7 @@ describe Zoomifier::ViewHelpers do
   end
 
   it "should generate the zoomify markup" do
-    @view.zoomify_image_tag('foo.jpg', { :id => 'foo' }).should ==
-      '<div id="foo"><img src="foo.jpg" alt=""/></div>'
+    @view.zoomify_image_tag('foo.jpg', { :id => 'foo', :alt => 'Foo Bar' }).should ==
+      '<div id="foo"><img alt="Foo Bar" src="/images/foo.jpg" /></div>'
   end
 end