Grunt imagemin running but not minifying

Question

Image-min is running normally but i get 0 images minified why?

after run the code on my terminal:

    $ grunt imagemin
    Running "imagemin:dist" (imagemin) task
    Minified 0 images (saved 0 B)

Done, without errors.

I am not understand, I tried loads different images and still not compressing.

imagemin part on my grunt:

//Image min ===============================

            var imagemin;
            config.imagemin = imagemin = {};
                imagemin.dist = {
                     options: {
                            optimizationLevel: 5,
                            progressive: true,
                          },
                    dynamic: {
                        files: [{
                            expand: true,
                            cwd: 'assets/images',
                            src: ['**/*.{png,jpg,gif}'],
                            dest: 'public/images'
                        }]
                    }

                };  

Answer 1

my problem was: dynamic: { }, should not have there, in their documentation they just explain how to use dynamic and static but should not have that in the code. its a bit confuse but anyway I fixed.

code without the dynamic {}.

//Image min ===============================

            var imagemin;
            config.imagemin = imagemin = {};
                imagemin.dist = {
                     options: {
                            optimizationLevel: 5,
                            progressive: true,
                          },

                        files: [{
                            expand: true,
                            cwd: 'assets/images',
                            src: ['**/*.{png,jpg,gif}'],
                            dest: 'public/images'
                        }]

                };