Given that it's a static site, why the JS requirement? Most browsers already intelligently handle keeping the "right" number of assets in memory, do you believe your JavaScript handles it better?
Also, it's not at all responsive to different viewport sizes; this might be a good thing to address.
I'd actually agree that most static sites shouldn't require js. For image galleries though it really needs the lazy loading to save bandwidth imo.
Also it's "sort of" responsive, it just doesn't handle window resize right now. I didn't think that was an important use case, but now multiple people have pointed it out so I'll add it.
Also, it's not at all responsive to different viewport sizes; this might be a good thing to address.
EDIT: Oof, that's a kick in the karma. Aah, well.