var ScreenshotReporter = require('protractor-simple-screenshot-reporter');

exports.config = {
  ...

  onPrepare: function() {
    jasmine.getEnv().addReporter(new ScreenshotReporter({
      directory: 'tmp/screenshots',
      filename: ':dir/:spec.png'
    }));
  },

  ...
};

jasmine.getEnv().addReporter(new ScreenshotReporter({
  filename: function(spec) {
    // Group into passed/ and failed/ directories
    return [':dir', spec.status, ':spec.png'].join('/');
  }
}));

{
  directory: 'tmp/screenshots', // The directory to save screenshots to
  filename: ':dir/:spec.png',   // The filename pattern for the screenshot
  resetEachRun: false           // If true, clears the directory each run
}