Access your Enroll Form by going to My Company > Forms > Enroll Form. Under the section you want to add a field, click the plus button and a list of the field elements will appear. Choose the "Formatted Content" option.
To add an image, click on the image icon within the Advanced settings. NOTE: The image has to be hosted somewhere. This can be in Google Photos (not Google Docs).
Here are the steps:
Click the image to open it in Google Photos (or wherever you are hosting the image)
Right-click the image and select "Open the image in a new tab"
Right-click the image again and select "copy image address"
Post the image address into the "Source" box
A size should pop up under "width" and "height." Adjust this to fit the space. (NOTE: If the size does not show up, the source is not correct.)
Save