importScripts("../lib/jimp.min.js"); self.addEventListener("message", function(e) { Jimp.read(e.data).then(function (lenna) { lenna.resize(256, Jimp.AUTO) // resize .quality(60) // set JPEG quality .greyscale() // set greyscale .getBase64(Jimp.AUTO, function (err, src) { self.postMessage(src); self.close(); }); }); });