Image_tag.blank? - paper clip - Ruby on rails

I just installed paperclip into my ruby ​​on rails application. Everything works great ... too great. I am trying to figure out how to tell paperclip not to output anything if there is no record in the table, so that I have no broken image links all over the place. How and where can I do this?

Here is my code:

class Post < ActiveRecord::Base

  has_attached_file :photo, :styles => { :small => "150x150"}
  validates_presence_of :body, :title
  has_many :comments, :dependent => :destroy
  has_many :tags, :dependent => :destroy
  has_many :ugtags, :dependent => :destroy
  has_many :votes, :dependent => :destroy
  belongs_to :user
  after_create :self_vote
      def self_vote
       # I am assuming you have a user_id field in `posts` and `votes` table.
       self.votes.create(:user => self.user)
      end

  cattr_reader :per_page 
    @@per_page = 10

end

      

        
        
        
      

    

View

<% div_for post do %>
    <div id="post-wrapper">
        <div id="post-photo">
            <%= image_tag post.photo.url(:small) %>
            </div>
    <h2><%= link_to_unless_current h(post.title), post %></h2>
    <div class="light-color">
    <i>Posted <%= time_ago_in_words(post.created_at) %></i> ago
    </div>
    <%= simple_format  truncate(post.body, :length => 600) %>
    <div id="post-options">
    <%= link_to "Read More >>", post %> | 
    <%= link_to "Comments (#{post.comments.count})", post %> | 
    <%= link_to "Strings (#{post.tags.count})", post %> | 
    <%= link_to "Contributions (#{post.ugtags.count})", post %> | 
    <%= link_to "Likes (#{post.votes.count})", post %>
    </div>
    </div>


<% end %>