Many thanks for the reply.
Thanks to your suggestions, I managed to place an image on the homapage that is unique to that page only. However, it seems I am not able to go beyond the limits defined by the 1024 value set under Template>Styles>Body>"Page Width".
As you can see in the attachment, the image standing behind the sign up form is the image I added using the CSS code. I tried using different rules to control the image size, including background-size: cover; but the image hits a hardwall on that 1024 px limit.
By contrast, the blurred image I load under Template>Styles>Body>"Background Image" reaches all corners of the screen.
Essentially, I would like for the image I load with the custom CSS code to behave as the image I load via the background control with "Styles". Do you have any suggestions on how this could be achieved?