<img src="clean_wave.jpg?" alt="Clean_wave"><%= image_tag("clean_wave.jpg?", :class => "img_preview") %>
<img src="clean_wave.jpg?" alt="Clean_wave">
%= image_tag(
"clean_wave.jpg?"
, :class => "img_preview") %>
<img> to image_tag
原文：http://www.cnblogs.com/iosdev/p/4013144.html
