google pagespeed/insights

[gsmlover4u]

google pagespeed/insights error
i am not understanding what to do
images are uploaded in image directory
http://www.example.com/images/buttons/collapse.png (expiration not specified)
http://www.example.com/images/buttons/collapse_40b.png (expiration not specified)
http://www.example.com/images/buttons/lastpost-right.png (expiration not specified)
http://www.example.com/images/buttons/newbtn_middle.png (expiration not specified)
http://www.example.com/images/buttons/search.png (expiration not specified)
http://www.example.com/images/gradients/gradient-grey-down.png (expiration not specified)
http://www.example.com/images/gradients/gradient-greytowhite.png (expiration not specified)
http://www.example.com/images/gradients/grey-up.png (expiration not specified)
http://www.example.com/images/gradients/selected-tab-gradient-with-top-alpha.png (expiration not specified)
http://www.example.com/images/icons/icon1.png (expiration not specified)
http://www.example.com/images/icons/icon2.png (expiration not specified)
http://www.example.com/images/icons/icon4.png (expiration not specified)
http://www.example.com/images/icons/icon7.png (expiration not specified)
http://www.example.com/images/misc/arrow.png (expiration not specified)
http://www.example.com/images/misc/facebook_login.gif (expiration not specified)
http://www.example.com/images/misc/forum_stats.png (expiration not specified)
http://www.example.com/images/misc/legend.png (expiration not specified)
http://www.example.com/images/misc/navbit-home.png (expiration not specified)
http://www.example.com/images/misc/pak-gsm.gif (expiration not specified)
http://www.example.com/images/misc/rss_40b.png (expiration not specified)
http://www.example.com/images/social%20icons/facebook.png (expiration not specified)
http://www.example.com/images/social%20icons/googleplus.png (expiration not specified)
http://www.example.com/images/social%20icons/linkedin.png (expiration not specified)
http://www.example.com/images/social%20icons/twitter.png (expiration not specified)
http://www.example.com/images/statusicon/category-16.png (expiration not specified)
http://www.example.com/images/statusicon/forum_link-16.png (expiration not specified)
http://www.example.com/images/statusicon/forum_new-16.png (expiration not specified)
http://www.example.com/images/statusicon/forum_old-16.png (expiration not specified)
http://www.example.com/images/statusicon/forum_old-48.png (expiration not specified)
http://www.example.com/images/statusicon/post_old.gif (expiration not specified)
http://www.example.com/images/statusicon/subforum_old-48.png (expiration not specified)
http://www.example.com/mobiquo/smartbanner/ads.js (expiration not specified)
http://www.example.com/mobiquo/smartbanner/appbanner.css (expiration not specified)
http://www.example.com/mobiquo/smartbanner/appbanner.js (expiration not specified)

[final kaoss]

It's pretty much saying that the resources listed are not being cached due to there not being an expiration time. In turn this means that every visit must redownload every resource listed instead of saving it to local cache. Anywhere from one day and up to a maximum of one year is acceptable.

Here's a small quote from gtmetrix to help you understand.

http://gtmetrix.com/leverage-browser-caching.html
In this file we will set our caching parameters to tell the browser what types of files to cache.

## EXPIRES CACHING ##
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/jpg "access plus 1 year"
ExpiresByType image/jpeg "access plus 1 year"
ExpiresByType image/gif "access plus 1 year"
ExpiresByType image/png "access plus 1 year"
ExpiresByType text/css "access plus 1 month"
ExpiresByType application/pdf "access plus 1 month"
ExpiresByType text/x-javascript "access plus 1 month"
ExpiresByType application/x-shockwave-flash "access plus 1 month"
ExpiresByType image/x-icon "access plus 1 year"
ExpiresDefault "access plus 2 days"
</IfModule>
## EXPIRES CACHING ##

Depending on your websites files you can set different expiry dates. If certain types of files are updated more frequently, you would set an earlier expiry date on the (ie. css files)

When you are done save the file as is and not as a .txt file.