gistfile1.rb

  def get_user_image(user)
    image_html = ""
    unless user.nil?
      if user.avatar?
        image_html += image_tag(user.avatar.thumbnail, {:height=>'50px',:width=>'50px'})
      elsif user.fb_user_id
  			image_html += '<fb:profile-pic linked="false" uid="' + user.fb_user_id.to_s + '"  size="square" ></fb:profile-pic>'
  		else
		    image_html += gravatar_for(user)#"/images/default_user.png" height="50px"
		  end
	  end
	  
	  return image_html
  end