When viewing an email in Outlook, the HTML can be dynamically modified by an email filtering service. A common email filtering service is provided by McAfee. The email filtering service can dynamically replace the HTML source code for the email's images and replace them with a transparent image/gif. When this occurs, there will be a whitespace in place of the image within your email in Outlook.
You can verify this by following the steps below to view the email's source code:
- Navigate to your email in Outlook and double-click on the message to open it in a new window or select View > Open in New Window.
- Click on Actions > Other Actions > View Source.
- In the Source Code, locate an Images source tag by searching for "src"
If you see the above source for your Images, this is a result of McAfee's email filtering service dynamically replacing the content with a transparent image. If you see this within your emails you will need to work with
your IT Team to adjust the content filter settings within your email filtering service.