You want a background image in a node or a view...without writing CSS. This module does the job..
Optional: Make an image style that can be used for the background. Ik made the image 70% transparent, using the Image Effects module.
1) for a node
Add a image field en set the display als a bouckgroun. You can even choose a responsive background. I chose my own imagestyle. The selecor is important. The background is set at the whole body. You can change this of course..
The result. Whenever i look at a node the corresponding image wil be shown.
Look at the configurations.. Even media can be set for showing the background only for big screens for example.
2) for a view. Make a block view en put the display of the imagefield as background. Give the block a place (eg content). Filter where you want te block to be shown.
A view with painters. A painting is generated at random for the background.