dropzone.js没有在容器内显示图像，而是逐个显示

why my dropzone implementation images goes to next line,i want to display it inline block as per official demo.

here is my basic configuration in laravel

                  <div class="form-group">
                           <div>
                              <div class="col-md-12">
                                     {!! Form::open([ 'url' => ['/contactuspagebanner'], 'files' => true, 'enctype' => 'multipart/form-data', 'class' => 'dropzone', 'id' => 'contactUsPageBanner' ]) !!}
                                    </form>
                                </div>
                              </div>
                         </div> 

my resulting image display is like this, the image appear like this

my question is? how to display this images while drop, inside a container rather than one by one. as seen in the dropzone example,other functionality i can take care of. [what css and js should i include]. i wanted to achieve result like this.. i wanted to achieve result like this

--please help me