The option for Email Body (Templates, Review Emails) that allows for HTML must be enabled in order to add images to the email template. To verify,

1. Launch the RSA Via L&G portal under Admin > System.  
2. Click on the Security tab and scroll to the section labeled XSS/Scripting Security.
3. For Email Body (Templates, Review Emails), confirm that Allow sanitized HTML is enabled. 

4. Once the setting is verified, you can add HTML tags to the email template under Admin > Email >Template in order to add an image.  

Sample HTML
If the logo/image location is https://hostname:port/aveksa/custom/images/logo-main.png, you can add sample HTML tag to add logo-main.png at the header of the notification email, as in the sample code below:

<img src="https://hostname:port/aveksa/custom/images/logo-main.png" /> 
<div> 
<p style="background-color:#425563"> 
<b><font color="#FFFFFF">New Review</font></b><font color="#FFFFFF"> </font></p> 

A new review has been generated. 
Review Details: 
Review Definition: {$reviewDefinitionName} 
Review: {$reviewName} 
Owner: {$reviewOwner} 
Date Generated: {$reviewCreationDate} 
Is Actionable : {$isReviewActionable} 
{$reviewDetailURL} 
You are receiving this email because you are the designated reviewer for "{$reviewName}". 

Thank you, 

User Access Governance