partial refresh help

Hi everybody!!!
I want to refresh automatically alements from my web page, but I don´t
know what Ihave to do.
Here is my view

<h1>Hello world/h1>
<%= link_to "My blog", posts_path %>
<img src="\guarrada\guarrada/foto.jpg" />
<img src="\guarrada\guarrada/foto2.jpg" />

The img tag are the elements I wanna to refresh

Someone can help me

Thanks a lot!!!!!!!!