I've hired incapsula.com performance services for my wordpress blog, and one of their techs is telling me this about the performance of my website:
On important note, yoursite.org returns the Vary caching header on User-Agent. This will reduce caching and acceleration performance dramatically (!!!). Why are you using Vary on User Agent for images? Is it possible to disable it?
As I use W3 Total Cache, I guess this 'Vary on User Agent for images' was activated by this plugin. My question:
How can I deactivate this 'Vary on User Agent for images' from W3TC that this tech is talking about? I tried to find such an option but can't find it inside W3TC menu.
I appreciate any light on this.
Thanks a lot.