Background image in Dashboard 2.0

What I always do to keep my web resources (images etc.) self-contained and not rely on external connectivity, is to specify one or more local httpStatic hosting roots in settings.js, and load from there.
For example, in settings.js define something like:

httpStatic:[ {path:"C:/ProgramData/Node-red/WebRoot", root:"assets"} ]

then refer to it as

/assets/images/pic1.jpg

You should not use the dashboard's native dist location as it gets wiped out upon dashboard version upgrades