You can’t unshare digital photos or be sure that they will be seen only by the people you want to see them. A friend (or someone you thought was a friend) could take a screen grab and forward it to everyone he knows. But there are a few ways to reduce the risks.
Some services, including Facebook, have automatic tagging features that suggest the name of the people in a photo. But not everyone wants to be identified in every shot—it can be unsettling and even creepy.
You can control who tags your own posts, and you can remove tags of yourself that others have posted. Check all of the privacy settings to see what the defaults are. Also look for tools to limit who sees your photos and the information contained in them.
Public or private?
Photos have a habit of traveling fast and far afield on Facebook and Instagram. On Facebook, the default setting is for sharing with friends. But you can be more selective: Use the drop-down menu next to the Post button and choose Custom. Our video (below) shows you how to check all of your Facebook privacy settings.
On Instagram, the default setting for posts is Public, so anyone can see your photos. You’ll need to turn on the Photos Are Private switch under Edit Your Profile. But privacy policies change, so there’s no guarantee photos won’t wind up in the public eye.
The geotag red flag
Digital photos carry more information than you might think. Each image file created by a phone or camera has Exchangeable Image File Format (EXIF) "metadata" that can include everything from exposure settings to the location. Phones and cameras with GPS sensors can embed EXIF geotags into photos—turning a casually posted vacation pic into an open letter to thieves that you’re not home.
Facebook says that it strips EXIF data from uploaded photos in the interest of user privacy. But Picasa, Photobucket, and Flickr still support it.
Editor's Note: This article also appeared in the June 2014 issue of Consumer Reports magazine.