Meagan Longoria has some tips for using layout images in Power BI:
Using layout images in Power BI has become a popular design trend. When I say layout images, I’m referring to background images with shapes around areas where visuals are placed. This is different from the new wallpaper feature that became available in the July release, which can be used to format the grey area outside your report page and extend the main color of background images.
Layout images can help with spacing and alignment within a report and can help create consistency across reports. They can also help create affordances, using consistent layout and design to make it obvious how users should interact with our reports.
I use layout images in some of my reports, but I don’t think they are necessary on every report. There are a couple of things to consider when using layout images.
Read on for an example of a good layout image versus a bad layout image as well as tips and tricks on how to create good layout images.