Hi,
I just quickly checked your site and run it through Google PageSpeed
There are some easy things you can tweak to get have faster pages and better PageSpeed rank.
For eg. on your product page in "Related Products" section you are showing "_large" images for products, but your CSS is allowing images to be only 263px in width (and height is autom. calculated) . "large" image in shopify is 480x480px, there is no need to show large image there, when you can show "medium" size (240x240px).
Similar problem is in section below that - "Related items" (also consider renaming that, it's repetitive, maybe use some like: "Customer also liked" or some other phrase). There you are limiting images to 150px with css and then showing images with size "medium". You can use "compact" size which is 160x160px, it's gonna be perfect for that section
Again, on the right side, you have "Top related items", showing "medium" images but CSS size of image is 68x68px, you can use Small size 100x100 or Thumb size 50x50 and tweak your css to match that size.
You can find more about Shopify image sizes here: https://docs.shopify.com/themes/liquid-documentation/filters/url-filters#size-parameters
I noticed that there is room for more image compression as well, tested few images, think you can get ~ 5% more if you use latest loessless algorithams like Mozilla MozJPEG
I created an app image compression called Crush.pics, it's using latest open source algothams, like MozJPEG. If you want to test it I can give you free 500MB/month of compression. I think you will see ~ 5% drop if image size.
Compressing images will improve your PageSpeed score, here is one example from our test sites:
• before compression PageSpeed score is 56/100: https://goo.gl/HBg3ay
• after compression PageSpeed score is 87/100: https://goo.gl/fl3NXv
Cheers,
Dom
