Requested icon is returned as white empty image

No that was not wrong and in any way appreciated. Please do not take my answer as a discouragement or as an unfriendly counter argument. The situation is pretty simple. Working on the documentation is pretty time consuming and - while I still try to invest some - I honestly do not have as much spare time as would be needed.

I still hope for others to contribute content. That can be done via an Issue or as a Pull Request. A two sentence howto was posted here: Documenting openHAB 2 - #153 by Dim

I’ll look at your contribution from the 24th now and try to include it today.