Laravel 5.5 update image

I'v created a form to update the table 'organizer'. My problem is that the image wont update. I've already added enctype="multipart/form-data" to my form.

If I set the validation of the image to required, laravel throwes the error "The logo must be an image". It seems that my ImageController doesn't get the image file . But why does the Controller get all the other data like the description, name ..?

All the other data in the table 'organizer' is updating without problems!

Form

    <form class="form" enctype="multipart/form-data" action="/organizer/update/">
        <input type="hidden" name="_method" value="PUT">
        <input type="hidden" name="_token" value="">
        ...
        other input fields...
        ...
        <label>Logo</label>
        <input type="file" name="logo" id="logo" accept="image/*"/>

        <button class="btn-add" type="submit">@lang('Save')</button>
        </form>

Controller (only the code for updating the image)

        if($request->hasFile('logo')){
        // ADD NEW lOGO
        $logo = $request->file('logo');
        $logo_name = $request->name.'_logo'.time().'.'.$logo->getClientOriginalExtension();
        $request->logo->move($destinationPath, $logo_name);
        $oldFilename = $organizer->logo;
        // UPDATE DATABASE
        $organizer->logo = $logo_name;
        // DELETE OLD lOGO
        Storage::disk('public')->delete("organizer/$oldFilename.jpg");
    }

via Chebli Mohamed