html - Rails image link_to not working -

this working fine

 <%= link_to "up.png", voteup_path(post_id: post.id, topic_id: post.topic_id), class: "xta"  %> 

but not this

 <%= link_to image_tag("up.png"), voteup_path(post_id: post.id, topic_id: post.topic_id), class: "xta"  %> 

please tell me how can make work.

try this, pass image_tag , class link_to tag

<%=link_to( image_tag("up.png"),voteup_path(post_id: post.id, topic_id: post.topic_id), class: "xta") %>