NotWritableException Can't write image data to path - php

Question

How to store an avatar correctly
(in developer mode) The way I have my Controller now
it stores the new image path to the database but doesn't upload it to the 'uploads/avatars' folder.
Also when I try to just edit the profile without uploading a new avatar, it throws an ErrorException undefined variable:avatar,
and the version i have on my hosting server also throws the Errorexception if not uploading but only editing the profile,
And if I try to upload a new avatar it tells me
NotWritableException
Can't write image data to path (/home/vlindr.com/vlindr/public/uploads/avatars/1504691841.jpg)
Anybody knows how to go about fixing this?
My Controller:
<?php
namespace App\Http\Controllers;
use Illuminate\Http\Request;
use App\Http\Requests;
use Auth;
use Session;
use Image;
use Illuminate\Support\Facades\File;
use App\User;
use DB;
use Illuminate\Support\Facades\Storage;
class UserController extends Controller
{
public function __construct()
{
$this->middleware('auth', ['except' => ['index', 'show']]);
}
//
public function index(){
return view('profiles.profile', array('user' => Auth::user()) );
}
public function edit()
{
return view('profiles.edit')->with('info', Auth::user()->profile);
}
public function update(Request $request)
{
$this->validate($request, [
'location' => 'required',
'about' => 'required|max:355',
'passion' => 'required|max:355'
]);
Auth::user()->profile()->update([
'location' => $request->location,
'about' => $request->about,
'passion' => $request->passion
]);
$user = User::find(Auth::user()->id);
// Handle the user upload of avatar
if ($request->hasFile('avatar')) {
$avatar = $request->file('avatar');
$filename = time() . '.' . $avatar->getClientOriginalExtension();
}
// Delete current image before uploading new image
if ($user->avatar !== 'man.png' && $user->avatar !== 'woman.png')
{
$file = public_path('/uploads/avatars/' . $user->avatar);
if (File::exists($file)) {
unlink($file);
}
}
Image::make($avatar->getRealPath())->resize(350, 350)->save( public_path('/uploads/avatars/' . $filename ) );
$user = Auth::user();
$user->avatar = $filename;
$user->save();
return back()->with('msg', 'Profiel is bijgewerkt');
}
}