A picture might be worth a thousand words, but could it also be worth a thousand dollars? New technology by MasterCard and Amazon may mean that the new hammock you’ve been eying online is only a camera flash away.

Earlier this month, MasterCard launched its “selfie-pay” biometric authentication application in Europe. Through the MasterCard app, cardholders can confirm an online payment by showing their face to the smartphone’s camera. To ensure that a real person is on the other end of the camera ― and not an imposter with the accountholder’s photo ― the app requires that the user blink to confirm that the cardholder’s real face is in the shot. The selfie payment option has been rolled out in Austria, Belgium, the Czech Republic, Denmark, Finland, Germany, Hungary, the Netherlands, Norway, Spain, Sweden and the UK, and is expected to be introduced worldwide next year.

Amazon is also getting in on the action. Earlier this year, Amazon applied for a patent on technology that would allow smartphone or tablet users to snap a photo or video of themselves instead of entering their password when making a purchase on Amazon’s app or mobile website. Much like MasterCard’s blinking requirement, the app may prompt the user to wink, smile, or tilt their head to confirm that a photograph isn’t substituted for a live person. The app could then analyzes the photo or video using existing technology, like facial recognition and motion detection software, both to determine if the user is a “real” person and to verify the user’s identity.

Both MasterCard and Amazon cite both convenience and security as the reasons behind their development of pay-by-selfie technology. Long, complex passwords may be secure, but they’re often hard to remember. On the other hand, easy-to-remember passwords are all too often just as easy for hackers to guess. Amazon’s patent application also notes that “The entry of these passwords … can require the user to turn away from friends or co-workers when entering a password, which can be awkward or embarrassing in many situations.” Query whether taking a selfie in that scenario is any less awkward.

While the pay-by-selfie idea is unique, the concept isn’t entirely new. In recent years, online retailers and app developers have been using biometrics to facilitate easier and more secure transactions. In the iTunes store, for example, iPhone users can use the built-in fingerprint scanner to authenticate their purchases instead of entering their AppleID password.

Although MasterCard and Amazon have touted their biometric payment options as more secure than a traditional password, in the wrong hands these fingerprints and photos could potentially allow hackers to pose as consumers to make online purchases or even cash advances. The proponents of this technology – as well as the retailers accepting “pay by selfie” payments – should be aware of these risks, as well as data privacy laws aimed at protecting their customers’ information.