The stylesheet and html are autogenerated; if you want to alter them please edit the pug template or less stylesheet, e.g. from the command line as follows:
I had to hack the included Croppie plugin to allow the user to upload images from their own computer without falling foul of CORS restrictions. So the version bundled here is non-standard. It's a one-line change:
* do a 'branching tree' approach to finding the closest tile? i.e. create a 1x1, 2x2, 4x4 version of each tile, so all the broadly darker tiles will sit under '0' and lighter tiles under '1', then tiles that are lighter at the top will sit under '1100', etc... I'm not sure how much more effective this will be or whatever it will give better/faster results but it's worth a try
* give heavier weighting to edge pixels when finding a matching tile? (thanks Mark)
* break up rendering into separate preview and output modes (would be good to have a throttled preview for brightness slider adjustments and then a debounced tile render)