Currently, setting publicPath: "auto" results in a stats file with:

{ "status": "done", "assets": { "lib/css/layers.416d91365b44e4b4f477.png": { "name": "lib/css/layers.416d91365b44e4b4f477.png", "path": "/Users/casey/build/public/lib/css/layers.416d91365b44e4b4f477.png", "publicPath": "autolib/css/layers.416d91365b44e4b4f477.png" }, ... }

"auto" is just prepended to publicPath. Which of course won't work out of the box. Considering "auto" is the default value in Webpack, it might be nice to support setting publicPath: "auto" and add a PUBLIC_PATH option to the loader config that would handle concatenation for us. We're using a custom LOADER_CLASS in the meantime.