[eluser]Exxon[/eluser]
Hi let me see if I can help you. To cache images, css and js you can use .htaccess.
Code:
#Caching
# Turn on Expires and set default to 0
ExpiresActive On
ExpiresDefault A0
# Set up caching on media files for 1 year (forever?)
<FilesMatch "\.(flv|ico|pdf|avi|mov|ppt|doc|mp3|wmv|wav)$">
ExpiresDefault A29030400
Header append Cache-Control "public"
</FilesMatch>
# Set up caching on media files for 1 week
<FilesMatch "\.(gif|jpg|jpeg|png|swf)$">
ExpiresDefault A604800
Header append Cache-Control "public"
</FilesMatch>
# Set up 2 Hour caching on commonly updated files
<FilesMatch "\.(xml|txt|html|js|css)$">
ExpiresDefault A7200
Header append Cache-Control "proxy-revalidate"
</FilesMatch>
# Force no caching for dynamic files
<FilesMatch "\.(php|cgi|pl|htm)$">
ExpiresActive Off
Header set Cache-Control "private, no-cache, no-store, proxy-revalidate, no-transform"
Header set Pragma "no-cache"
</FilesMatch>
#Caching
Just note this is intense caching and can be pain while still in development or changing images so customize it to suit you.
About the codeigniter cache you will have to wait for someone who actually knows how it works, not one of my websites have ever grown so much that I need cache so I have no idea. Sorry