Here’s resources that will help you make your site faster! I don’t recommend anything I don’t think is great for you; some links are affiliate links to support the site.
Books:
High Performance Images by Colin Bendell, Tim Kadlec, Yoav Weiss, Guy Podjarny, Nick Doyle & Mike McCall from O’Reilly Press
High Performance Browser Networking by Ilya Grigorik
Designing for Performance by Lara Callender Hogan
Podcasts: