Wow looks great, congratulations both for the website and your photography! Must have taken some time to create all those galleries ... good work. It's a pleasure to view the galleries and images, and easy to navigate.
Your server seems nice and fast also ... I'm impressed that it handles the "preload site object" without any problems. You might want to keep an eye on this setting though ... It's a very large site to use a preload, but seems to work ok.
A few minor issues I noticed, which you might want address:
- Your server does not support GZIP compression.
This is not really a big problem, because it really only applies for page documents, which will load fast anway from your server. However, it does affect your preload site object, which weighs in at 2MB un-compressed. If gzip was enabled, the site object would likely compress down to 2-300 KB. If your host doesn't allow GZIP compression, you could alleviate the issue by passing your server through Cloudflare, as explained in this post.
- Missing Favicon
You don't seem to have the favicon.png file http://www.nubierocce.it/content/custom ... avicon.png, so browsers show a load error in the console ... Did you upgrade from an earlier version of X3? If so, you should create a folder "favicon" inside the "custom" folder, and add a 32x32 px favicon.png file.
- Default Preview Image does not exist.
Not important, but you might want to update your default preview file under settings -> page -> details. Check your diagnostics here nubierocce.it/?diagnostics Default Preview Image does not exist