get rid of https://upload.wikimedia.org/wikipedia/commons/a/a2/Pixel-white.png

[ensonic]

What about using a dataurl instead of referencing the pixel from wikimedia:
Using http://png-pixel.com/ the replacement would be:

data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8/x8AAwMCAO+ip1sAAAAASUVORK5CYII=

The wikimedia url is used in two files.

[jihoonl]

sensors/Particles.js uses the wikimedia url.

[jihoonl]

I will mark it as help wanted.

[MatthijsBurgh]

This is fixed by #218