Google’s page insights and firefox’s Yslow keep telling me I should ‘Leverage browser caching for the following cacheable resources:’ and lists all my images + ‘(expiration not specified)’.
I have read google’s recommendations and have searched for how to do this, but am still confused.
Google says ‘Each resource should specify an explicit caching policy that answers the following questions:
whether the resource can be cached and by whom, for how long, and if applicable, how it can be
efficiently revalidated when the caching policy expires.’
I assume an image is a ‘resource’? So can I assign a caching policy to each individual image?
Search results suggest to apply the rules to image types through the apache config. I run a number of sites through one server and don’t want them all to be the same.
I’d rather do it on a page-by-page basis if possible.
Can anyone advise, what are the options.