We have to acknowledge that if the manual process of optimizing images can be quite tedious and time consuming in the scenario where many images need to be resized and optimized, doing it manually may not be the best idea.
There are a few third-party and server-side services out there that automate this process for us. We're going to leave the tutorials of how to implement these services for another book. However, we're going to list some of the most popular services so you can have a reference in case you want to dive deeper.
Here are a few examples of third-party image resizing services:
Here are a few examples of server-side (.htaccess and/or .php) image resizing services: