2018 is end of life and 2019 will be released soon. Autoptimize 2.5 is not at that point yet, but I just pushed a version to GitHub which adds image lazy loading to Autoptimize;
The actual lazy-loading is implemented by the integrated lazysizes JS lazy loader which has a lot of options some of which I will experiment with and bring to Autoptimize to the default improve user experience.
If you want you can download the beta (2.5.0-beta2) now from Github (disable 2.4.4 before activating the beta) and start using the new functionality immediately. And if you have feedback; shoot, I’ll be happy to take your remarks with me to bring AO 2.5 ready for release (I’m targeting March, but we’ll see).