OK, interesting article and some quite effective tricks but this is not "optimization". Optimization means getting the best possible result from something, by some criterion. For example, blurring an image and then getting a bit better compression is not optimal. But if it could be shown that was getting the best possible compression for JPEG then it would be optimal.

The article should be called "Image Compression Tricks". I don't think any of the techniques are considered advanced in today's technology.