preg_replace error at the time of upload multiple image in laravel

I got error while uploading multiple image in laravel.

HTML Code :-

<div class="form-group">
<label for="title">Art Gallery</label>
 <input type="file" name="art_image[]" id="art_image" value=""  accept="image/*"  multiple="multiple">
</div>

:- Controller code

if ($request->hasFile('art_image')) {
   $fileImage1 = $request->file('art_image');
   $StoreName = array();
   foreach ($fileImage1 as $files) {
         $filename1 = time().rand(1,100).".".$files>getClientOriginalExtension();
     $StoreName[] = $filename1;
     if($files->move(ART_IMAGE_DIR_PATH, $filename))
         {
              $data['art_image'] = $filename1;
           }
        }
   $artdetail_model->art_image = serialize($StoreName);
     }

I got below error

preg_replace(): Parameter mismatch, pattern is a string while replacement is an array

via Chebli Mohamed