The PageSpeed Insights recommendations are about the
Browser Cache, and
Defer Parsing of CSS.
Please try to utilize a caching plugin like W3 Total Cache to fix the Browser Cache and Defer Parsing issues.
To optimize your images, you can try any of these plugins:
Smush Image Compression and Optimization
EWWW Image Optimizer
I also check your site on https://gtmetrix.com/ and most of the things that slow your site is coming from 3rd party sites resources (see screenshot below.)
Try following the guide we provided here, see the W3 TOTAL CACHE and Gzip Compression section.