var gulp = require('gulp'),
imagemin = require('gulp-imagemin'),
watch = require('gulp-watch');

gulp.task('imgmin', function(){
    return gulp.src('src/img/imgmin/*.*')
    .pipe(imagemin())
    .pipe(gulp.dest('src/img/'));
});

gulp.task('imgmin:watch', function () {
    return watch('src/img/imgmin/*.*', function () {
        gulp.src('src/img/imgmin/*.*')
            .pipe(gulp.start('imgmin'));
    });
});