This is a lecture that is absolutely necessary for front-end development. I wanted to learn about this optimization part, and this lecture was perfect for me. However, the content is a bit lacking. It feels like I only watched about 70% of a really good lecture. I think you were thinking of part 2, but it would have been better if you had explained image size optimization and cache in more depth. Overall, it was a lecture that was lightly skimmed, so I felt like I was learning concepts, but I didn't learn much in depth enough to be able to properly utilize them. I don't think I can erase the feeling that it was a bit of a waste of money. However, I think it will be an easy lecture for those who know nothing about optimization.