Your image work is rich and has lots of texture. But on the invisible side, the images are slowing down the load time. Investigate optimization alternatives like different image formats without compromising your art. Designers tend to think viewers care about image quality. It's actually down the list somewhere after speed, usability, navigation, and content. Yes. Even on portfolio sites. Viewers expect a little longer load time on portfolio sites but not as long as your HOME page is presently. The HOME page is NOT your portfolio. It's the pages that come after that. So viewers still have high expectations on that first page for load time.
It's taking 15 to 30 seconds to load the HOME page. You're target should be 7 seconds on highspeed or less. At 30 seconds, usability testing has shown, you've lost half your visitors already. Bail out. Speed is a transparent credibility feature. Viewers only notice slow sites not fast ones.
You're code looks beautiful. I'm jealous.
The page tile says design portfolio but it doesn't appear on the page. I'm a designer and on the HOME page I can't tell what it is you are "selling." After that on linked pages, it's obvious. The HOME page should tell me what you do, who you are, and why I should care. Just the title isn't sufficient. It's good for the search engines but not enough for a viewer. Make me want to explorer and discover.
If you want design work, consider a "Hire Me" link and page. This has been shown to improve portfolio websites response. Assuming you want work, of course.
Here's and example of how to optimize some images on the HOME page. The HOME page is the most critical. The background image is about 90K PNG. I switched it to a low color depth in GIF to half the file size, for me the effect is the same with much faster loading. You might also be creative with a smaller tiling effect that gives similar "theme" results.
The full-width banner images could be reduced to 30% of original weight by converting to high quality JPEGs. Small images like "think_sm-resizecrop-214-117.png" could be reduced 10 fold by using GIFs.
Those are just some examples.
Also, another way to speed up your pages is using GZIP-PHP to compress the code on-the-fly. Do you have PHP functions on your server / host? If so, I can tell you how to do this.
My challenge to you is finding out how fast you can make this site really load. Visitors will love you for it.