What is the best way to add art and complex drawings to the PCB?
Eagle supported bitmap importing which basically rasterized the image in whatever layer you wanted.
LibrePCB has a DXF option but this doesn’t seem to work well for drawings that have fill and voids.
My current work flow for this is to import the image into Eagle and make a part there and then import into LibrePCB.
Hmm this is a tricky case indeed. Especially the negative text is a problem. Unfortunately I have no recommendation other than what you already tried. I hope some day we can implement tools for this use-case.
Note that the Eagle approach is not good from performance perspective. As far as I remember, Eagle creates tons of small polygons which can cause massive performance degradation for rendering (maybe also for DRC, depending on layer).
yeah Eagle just makes tons of small lines but PCs are powerful enough now days that it doesnt seem to matter anymore 
I dont need Eagles particular implementation but getting graphics like this onto boards is something that is needed for the boards I make.
For example this is the board I did for this years DEFCON badge we built.
Huh yeah that’s crazy 
For long term of course we should provide such a feature built-in, but for short term probably the Eagle import is the only way (or create an own converter script e.g. in Python to covert images to LibrePCB polygons).
It just came into my mind, maybe this could be helpful: Svg2librepcb: CLI tool and Inkscape extension
