No, we do some client-side prefiltering to ignore non-products, and we also do some more extensive server-side filtering. We also allow you to cancel snap processing, as well as go into an "Ignore new snaps" mode via the settings in the app. Also, the upload only happens when the app is foregrounded, giving you further control.

I would strongly guess it's a fixed set of product images they're training against, possibly attained by massive scraping. Another part of training or processing might consist of a reverse image search API, like TinEye, and gathering metadata from the pages containing the result images.

We do our own searching and wrote our own crawlers. Does that answer your question?