There are all kinds of ways your picture can end up on the web without you putting it there. Perhaps you where at an event where pictures where taken and uploaded to Facebook. Perhaps your company has an employee profiles page. Perhaps you where photographed for your local newspaper a few years ago when you did that things. Saying "I haven't spread my photos thus they don't exist" is extremely naive.

Nope, your lifelong discipline of not publishing a single self-photo online will be undone by someone else who snaps a photo of you and posts it online.

Your picture might already be on the internet. Your friends may have uploaded a picture from a party or school reunion on Facebook. And since Facebook nagged them and they thought it'd be cool to tag you on the picture even though you don't have a Facebook account.

If you have a passport or drivers licens then the government, and thus the police, already have your picture.

I have a colleague / acquaintance who worked laboriously to prevent photos of himself being put online. He avoided all social media, tried to duck out of group photos and used pseudodyms for fora. Searching for him only returned photos of other people sharing his name.

Then one day last year he attended an open-day about retraining IT professionals as teachers. He didn't read the small print closely enough and photos taken at the event were published and studiously tagged by the event organisers. There he was, bubbling up on Google Images.

Subsequently he contacted the organisers and they did remove the tagging, but it was purely by chance that he had discovered it.

What if retail stores take your picture and then match it against your credit card at POS and then automatically identify you in the future as well? I can't imagine this is too far off, if it's not already happening.

I think exactly the opposite is true. "Personal spamming" will probably help you. Spread your photo as much as possible, all with different names and profiles :-)

Findface can't identify you, who are you, why are you walking past my house? I have never seen you before, I'm going to call the police, you're acting strange.