New Outlook Personalization Background image

Hello - generally I like the Outlook Mail client but the new one which it seems I'm forced to switch to this year seems to be a retrograde step. I have tried all the settings and can not make it nearly as compact as the previous version. Perhaps the biggest annoyance is that the old client allowed the background image (full screen) to be a user selected photo. Now it seems the choice is a plain colour or a fairly bland microsoft background. This does not seem like a complex capability but the lack of it is stopping me switching and prompting me to explore other clients. Have I missed something?