I just installed NextGen Gallery, I have used it before, in between my last usage and now, I think it got bought. I am sure a few versions came out since last time I used it.
I don't know what freemius.com is (if I do, I can't remember right now, It's been a long day).
When you install a browser, it asks you if it can collect usage data, no personal identifying information will be shared and so forth.
Many apps for Iphone, Android and whatever else, do the same thing.
How do you feel about that? How can you trust that only information 123 will be shared and not 456 and other personal information?
I AM NOT SAYING NGG WILL BREAK MY PRIVACY.
This is in general, not just for NGG.
Many sites have Google Analytics (or other kind of Analytics), that knows your browser, O/S, resolution, internet connection speed and so forth.