In case you are still looking for the answers: I faced the same issue 5 months back while working on my client’s website, which was related to?sublimation printers?and involved a lot of images and image sizes. I found a WordPress plugin that worked wonders for me: “Ewww image optimizer” by Exactly www and “web express” by Bjorn Rosell. Give these a try, and let me know how these worked for you.
