Rails switch case in the view

You should pull your first when into same block as case

<% @prods.each_with_index do |prod, index|%>  <% case index      when 0 %><%= image_tag prod.img, :id => "one") %>  <% when 1 %><%= image_tag prod.img, :id => "two") %>  <% when 2 %><%= image_tag prod.img, :id => "three") %>  <% end %><% end %>

Don't put to much logic in your views.

i would add a helper

def humanize_number(number)    humanized_numbers = {"0" => "zero", "1" => "one"}    humanized_numbers[number.to_s]end

than you can call it from the view with

<%= image_tag("#{prod.img}", :id => humanized_number(index)) %>

First, you should really think about abstracting this functionality into a helper method to avoid cluttering your views with logic.

Second, case statements are a bit tricky to use in ERB, because of the way erb parses the code. Try instead (not tested, as I don't have a ruby close to hand at the moment):

<% @prods.each_with_index do |prod, index|%>  <% case index    when 0 %>      <%= image_tag("#{prod.img}", :id => "one") %>    <% when 1 %>      <%= image_tag("#{prod.img}", :id => "two") %>    <% when 2 %>      <%= image_tag("#{prod.img}", :id => "three") %>  <% end %><% end %>

See this thread for more information.