Laravelで 画像リサイズと画像保存を簡易にできる方法 ref: https://qiita.com/ryuseikurata/items/3ba472e933f2f5bfe043

.....create_users_table.php

<?php

use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateUsersTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->increments('id');
            $table->string('name');
            $table->string('email')->unique();
            $table->string('avatar')->default('default.jpg');
            $table->string('password');
            $table->rememberToken();
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::drop('users');
    }
}

app.blade.php

<a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-expanded="false" style="position:relative; padding-left:50px;">
    <img src="/uploads/avatars/{{ Auth::user()->avatar }}" style="width:32px; height:32px; position:absolute; top:10px; left:10px; border-radius:50%">
    {{ Auth::user()->name }} <span class="caret"></span>
</a>

file0.txt

php artisan make:auth

file2.txt

$table->string('avatar')->default('default.jpg');

file3.txt

DB_DATABASE=(自分のデータベースの名前)
DB_USERNAME=（データベースに入るためのユーザの名前）
#DB_PASSWORD=secret(ローカル開発環境ならば、パスワードを設定しなくても大丈夫だと思います)

file4.txt

php artisan migrate:refresh

profile.blade.php

@extends('layouts.app')

@section('content')
<div class="container">
    <div class="row">
        <div class="col-md-10 col-md-offset-1">
            <img src="/uploads/avatars/{{ $user->avatar }}" style="width:150px; height:150px; float:left; border-radius:50%; margin-right:25px;">
            <h2>{{ $user->name }}'s Profile</h2>
            <form enctype="multipart/form-data" action="/profile" method="POST">
                <label>Update Profile Image</label>
                <input type="file" name="avatar">
                <input type="hidden" name="_token" value="{{ csrf_token() }}">
                <input type="submit" class="pull-right btn btn-sm btn-primary">
            </form>
        </div>
    </div>
</div>
@endsection

UserController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Http\Requests;
use Auth;
use Image;

class UserController extends Controller
{
    //
    public function profile(){
        return view('profile', array('user' => Auth::user()) );
    }

    public function update_avatar(Request $request){

        // Handle the user upload of avatar
        if($request->hasFile('avatar')){
            $avatar = $request->file('avatar');
            $filename = time() . '.' . $avatar->getClientOriginalExtension();
            Image::make($avatar)->resize(300, 300)->save( public_path('/uploads/avatars/' . $filename ) );

            $user = Auth::user();
            $user->avatar = $filename;
            $user->save();
        }

        return view('profile', array('user' => Auth::user()) );

    }
}

web.php

Route::post('profile', 'UserController@update_avatar');