[ruby-on-rails] link_to image tag. how to add class to a tag

I am using link_to img tag like following

<%= link_to image_tag("Search.png", :border=>0, :class => 'dock-item'), 
:action => 'search', :controller => 'pages'%><span>Search</span></a>

Which results in following html

<a href="/pages/search"><img alt="Search" border="0" class="dock-item" 
src="/images/Search.png?1264132800" /></a><span>Search</span></a> 

I want the class="dock-item" to go to the <a> tag instead of the img tag.

How can i change this?

Update:

<%= link_to image_tag("Search.png", :border=>0), :action => 'search', 
:controller => 'pages', :class => 'dock-item' %>

results in

<a href="/pages/search?class=dock-item"><img alt="Search" border="0" 
src="/images/Search.png?1264132800" /></a> 

Easy:

<%= link_to image_tag("Search.png", :border=>0), :action => 'search', :controller => 'pages', :class => 'dock-item' %>

The first param of link_to is the text/html to link (inside the a tag). The next set of parameters is the url properties and the link attributes themselves.

Just adding that you can pass the link_to method a block:

<%= link_to href: 'http://www.example.com/' do %>
    <%= image_tag 'happyface.png', width: 136, height: 67, alt: 'a face that is unnervingly happy'%>
<% end %>

results in:

<a href="/?href=http%3A%2F%2Fhttp://www.example.com/k%2F">
    <img alt="a face that is unnervingly happy" height="67" src="/assets/happyface.png" width="136">
</a>

This has been a life saver when the designer has given me complex links with fancy css3 roll-over effects.

Hey guys this is a good way of link w/ image and has lot of props in case you want to css attribute for example replace "alt" or "title" etc.....also including a logical restriction (?)

<%= link_to image_tag("#{request.ssl? ? @image_domain_secure : @image_domain}/images/linkImage.png", {:alt=>"Alt title", :title=>"Link title"}) , "http://www.site.com"%>

Hope this helps!

To respond to your updated question, according to http://api.rubyonrails.org/classes/ActionView/Helpers/UrlHelper.html...

Be careful when using the older argument style, as an extra literal hash is needed:

  link_to "Articles", { :controller => "articles" }, :id => "news", :class => "article"
  # => <a href="/articles" class="article" id="news">Articles</a>

Leaving the hash off gives the wrong link:

  link_to "WRONG!", :controller => "articles", :id => "news", :class => "article"
  # => <a href="/articles/index/news?class=article">WRONG!</a>

this is my solution:

<%= link_to root_path do %>
   <%= image_tag "image.jpg", class: "some class here" %>
<% end %>

Best will be:

link_to image_tag("Search.png", :border => 0, :alt => '', :title => ''), pages_search_path, :class => 'dock-item'

The whole :action =>, :controller => bit that I've seen around a lot didn't work for me.

Spent hours digging and this method definitely worked for me in a loop.

<%=link_to( image_tag(participant.user.profile_pic.url(:small)), user_path(participant.user), :class=>"work") %>

Ruby on Rails using link_to with image_tag

Also, I'm using Rails 4.

<%= link_to root_path do %><%= image_tag("Search.png",:alt=>'Vivek',:title=>'Vivek',:class=>'dock-item')%><%= content_tag(:span, "Search").html_safe%><% end %>

I tried this too, and works very well:

      <%= link_to home_index_path do %>
      <div class='logo-container'>
        <div class='logo'>
          <%= image_tag('bar.ico') %>
        </div>
        <div class='brand' style='font-size: large;'>
          .BAR
        </div>
      </div>
      <% end %>

You can also try this

<li><%= link_to "", application_welcome_path, class: "navbar-brand metas-logo"    %></li>

Where "metas-logo" is a css class with a background image