Neal, you need a proper certificate on your website. You're leading people to a "secure" self-signed certificate. That really doesn't look good. At all.
There's a rule in blog writing. It's unspoken, perhaps because it's so obvious. Your title should match your content. The title and even introductory paragraph say "performance" and then the follow up is a tutorial in image compression. I guess that -honesty- sounds too boring. The segue into image compression tutorial is well intentioned at best, but is borders on dishonesty...
The single most important technique to speeding up a web page is to make it smaller
You could have a google fiber connection requesting a 1KB website, and you won't get around two primary factors.
If your web server doesn't respond in 500ms or less, you have a slow web server. It should respond in under 200ms. Business-grade performance should be 100ms or less for anonymous users. If your website doesn't respond, that 1KB file isn't getting to you.
Use faster hosting – a faster, more responsive server decreases the total time between a visitor pressing enter (or clicking a link) and the page loading
This shouldn't be second, but it's not even entirely true. It's server optimization. You don't get faster and faster performance, with the same level of traffic, simply by purchasing bigger and bigger servers. Implementing Varnish, Redis, OpCache, modifying MySQL, adjusting the amount of memory available, the number of workers available and many other tweaks can easily improve web server performance by a few hundred percent. Scaling the right resources can save hundreds or thousands of dollars per month. Maybe it's just your hard drives which need more breathing room. Maybe you need more RAM to fullfil requests.
Next, if your 1KB file must travel a far distance, it can those precious seconds needed just to travel to its destination. This renders all of your optimization fruitless. Suddenly, optimization doesn't seem like the single most important factor; a CDN does. A CDN will respond with my assets quickly from a place which is likely much closer to my customer than my web server. As a bonus, all the traffic which is going to a CDN point of presence is not going to my web server.
It's not that image optimization is unimportant, I'm just disappointed this is yet another article which touches on performance from the "Page Speed" point of view. Yes, put your JS at the bottom when you can, gzip your files, add cache headers and of course optimize your images. But none of those things bring your site up to the kind of speeds which customers demand, and the kind of speeds which are making the "7% of sales" headlines.
Bandwidth shouldn't be disregarded, but it's no longer the precious commodity it used to be (Unless you're in Australia, but they're sleeping right now, so they don't care). We're not on dial-up anymore. Even our phones can reach 20Mbps. At some point, stop worrying about the precious few KB you might save on the front-end and start examining the services delivering your assets; you'll get much better results.