laravel image validation is always working even when the file is an image

i am trying to upload an image to my database the problem is when i use the validator , it always return tru showing the error the avatar file should be an image even when i am puttin an image , i tried jpeg,pjg and png but nothing seems to work

controller

 public function store(Request $request)
    {

        $this -> validate($request ,[
            //other validators working fine
            'avatar' => ['nullable', 'image' ],


    ]);

    if($request->hasFile('avatar')){
        // Get filename with the extension
        $filenameWithExt = $request->file('avatar')->getClientOriginalName();
        // Get just filename
        $filename = pathinfo($filenameWithExt, PATHINFO_FILENAME);
        // Get just ext
        $extension = $request->file('avatar')->getClientOriginalExtension();
        // Filename to store
        $fileNameToStore= $filename.'_'.time().'.'.$extension;
        // Upload Image
        $path = $request->file('avatar')->storeAs('public/avatars', $fileNameToStore);
    } else {
        $fileNameToStore = 'noimage.jpg';
    }

         $member= new Member;
         //other inputs working fine
         $member->avatar = $fileNameToStore;

         $member->save(); 
    }

view

<div class="form-group row">
                        <label for="avatar" class="col-md-4 col-form-label text-md-right">image du membre</label>

                        <div class="col-md-6">
                            <input id="avatar" type="file" class=" @error('avatar') is-invalid @enderror" name="avatar"  autofocus>

                            @error('avatar')
                                <span class="invalid-feedback" role="alert">
                                    <strong></strong>
                                </span>
                            @enderror
                        </div>
                    </div>

when i tired removing the validators it works and always getting noimage in the database

via Chebli Mohamed