How to allow download of images within emails
Some email clients may block images by default and will prompt the user if they'd like to load the images in the email content.
Depending on your email client, you can add the sender address to a safe senders list to allow images from those senders to load automatically. The instructions to do this will vary based on your email client.
Microsoft Outlook
To allow these on an individual basis on Outlook, please see the below Microsoft guide:
Block or unblock automatic picture downloads in email messages - Microsoft Support
This may also be configured via Group Policy as shown in the below Microsoft Guide:
Google Gmail
If you are in a Google environment, you may wish to follow the below guide on how to download images on Gmail:
Turn images on or off in Gmail - Computer - Gmail Help (google.com)