I got this error from Google Speed test:

The following cacheable resources have a short freshness lifetime. Specify an expiration at least one week in the future for the following resources:

```
http://localhost/english/favicon.ico (expiration not specified)
http://localhost/english/images/bg_center.png (expiration not specified)
http://localhost/english/images/bg_top.jpeg (expiration not specified)
http://localhost/english/images/footer_bg2.png (expiration not specified)
http://localhost/english/images/m_facebook.png (expiration not specified)
http://localhost/english/images/m_rss.png (expiration not specified)
http://localhost/english/images/top_bg.png (expiration not specified)
http://localhost/english/javascript/gram.js (expiration not specified)
http://localhost/english/javascript/top_start.js (expiration not specified)
http://localhost/english/jquery.js (expiration not specified)
http://localhost/english/style/gram.css (expiration not specified)
http://localhost/english/style/style.css (expiration not specified)

```

Should I do somthing in my htaccess file?