What does expiration not specified mean?
Here's a report on my website that I need some help with if you please. From GTmetrix:
"The following cacheable resources have a short freshness lifetime. Specify an expiration at least one week in the future for the following resources:
Screen Shot 2013-10-01 at 11.56.53 AM.png
I don't know much. Can you please explain and advise where and how to fix this?