How to delete old picture after new one uploaded

I have this in my Controller which handles image upload

public function updateProfileImage(Request $request)
    {
        $user = auth('api')->user();

        $image = $request->input('image'); // image base64 encoded
        preg_match("/data:image\/(.*?);/",$image,$image_extension); // extract the image extension
        $image = preg_replace('/data:image\/(.*?);base64,/','',$image); // remove the type part
        $image = str_replace(' ', '+', $image);
        $imageName = 'profile' . time() . '.' . $image_extension[1];
Storage::disk('public')->put($imageName,base64_decode($image));
$user->update($request->except('image') + [
            'profilePicture' => $imageName
        ]);

        return [
            //'Message' => "Success",
            'profilePhoto' => $user['profilePicture']
        ];

    }

How can i delete the old picture from the directory after new one has been uploaded.