add build process for images

gulpfile.js

+var gulp = require('gulp')
+var image = require('gulp-image');
+
+// paths
+let path = {
+  src: {
+    img: 'img/*',
+  },
+  dist: {
+    img: 'img/',
+  }
+}
+gulp.task('images', function () {
+  return gulp.src(path.src.img)
+    .pipe(image())
+    .pipe(gulp.dest(path.dist.img))
+})
+
+gulp.task('default', gulp.parallel('images'))
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