Hello Attila,
Yes it is possible to put background image for service or team posts. You can add background image from
For Service : Go to Dashboard –> Pages –> Services page –> Edit –> Select page background (right side options) –> Select “Use image as background” –> Set listing image.

For Team : Go to Dashboard –> Pages –> Team page –> Edit –> Select page background (right side options) –> Select “Use image as background” –> Set listing image.
Thank you.