We do not change the order of the photos, we just try to find a good set of breaking points inside that order.
Actually, Chromatic tries to read the EXIF "DateTimeOriginal" information to sort the photos and falls back to the "LastModifiedDate" if the former doesn't work.
Actually, you're right! It's the same picture, scaled down to around 500x500 and with a heavy gaussian blur applied to it. The trick is to have a subtle grain effect over it to eliminate gradient artifacts.
Yes, we figured the page scrolls slow if there are too many photos in the DOM at the same time so the lazy-load-function also removes them when out of scope.
Btw: just bought a copy of your app.