When you plug a camera or mobile device into a computer with the Dropbox desktop app installed, you’ll see a prompt asking if you’d like to enable camera uploads for that device. This means that if someone used your computer to charge their phone, they may have clicked OK to that pop-up without realizing it. To find out who uploaded photos to your account: Log in to dropbox.com. Hover over the photo you don’t recognize, and click the “…” (ellipsis). Click Version history. Look for a name next to Added by. If you don’t recognize the name, you can remotely sign out of any devices you’re currently signed in to.