image_tag is it just plain Broken?

I'm trying

<%= link_to image_tag("#{gallery.link_to}"), gallery_path(gallery)
unless gallery.thumbnail_id == 0%>

and get the error:

ActionView::TemplateError (undefined method `image_tag' for #<Gallery:
0xb7083be4>) on line #23 of app/views/users/index.rhtml

This is my definition of link_to
def link_to
    unless self.thumbnail_id == 0
      picture = Picture.find(self.thumbnail_id)
      path = picture.public_filename(:big_thumb)
      return "#{path}"
      return ""

Any idea about that error?

Wait, I think I fixed it! Nevermind, XD