Update nist-authentication-basics.md

Author: v-edmckillop

articles/active-directory/standards/nist-authentication-basics.md

@@ -89,7 +89,7 @@ SOFA-B framework to quantify biometrics strength:
 
 You can implement single-factor authentication by using an authenticator that verifies something you know, or are. A something-you-are factor is accepted as authentication, but it's not accepted solely as an authenticator. 
 
-  ![How single-factor authentication works](media/nist-authentication-basics/nist-authentication-basics-1.png)
+   ![How single-factor authentication works](media/nist-authentication-basics/nist-authentication-basics-1.png)
 
 ## Multi-factor authentication
 
@@ -105,14 +105,14 @@ MFA requires two authentication factors, which can be independent. For example:
 
 These methods enable two independent authentication transactions with Azure Active Directory (Azure AD).
 
-  ![MFA with two authenticators](media/nist-authentication-basics/nist-authentication-basics-2.png)
+   ![MFA with two authenticators](media/nist-authentication-basics/nist-authentication-basics-2.png)
 
 
 ### MFA with one multi-factor authenticator
 
 Multifactor authentication requires one factor (something you know, or are) to unlock a second factor. This user experience is easier than multiple independent authenticators.
 
-  ![MFA with a single multifactor authenticator](media/nist-authentication-basics/nist-authentication-basics-3a.png)
+   ![MFA with a single multifactor authenticator](media/nist-authentication-basics/nist-authentication-basics-3a.png)
 
 One example is the Microsoft Authenticator app, in passwordless mode: the user access to a secured resource (relying party), and receives notification on the Authenticator app. The user provides a biometric (something you are) or a PIN (something you know). This factor unlocks the cryptographic key on the phone (something you have), which the verifier validates.