image resize task.

gulpfile.js

var gulp        = require('gulp');
var filelog     = require('gulp-filelog');
var glob        = require('glob-all');
var imageResize = require('gulp-image-resize');

var paths = {
  srcDir : 'source/articles'
}

gulp.task( 'image-optim:thumb', function(){
  var image_dirs = glob.sync(['source/articles/**/images']);

  var resizeOptions = {
    width       : 200,
    height      : 200,
    gravity     : 'Center',
    crop        : true,
    upscale     : false,
    imageMagick : true
  };

  var imageminOptions = {
    optimizationLevel: 7
  };

  for(var dir in image_dirs) {
    var baseDir = image_dirs[dir];
    var srcGlob = image_dirs[dir] + '/origin/*.+(jpg|jpeg|png|gif)';
    var dstGlob = image_dirs[dir] + '/thumb';

    gulp.src( srcGlob )
      .pipe(filelog())
      .pipe(imageResize( resizeOptions ))
      .pipe(gulp.dest(dstGlob))
      .pipe(filelog());
    }
});

gulp.task( 'image-resize', ['image-optim:thumb'] );