title: Image uploaded through inertiajs form.post fails mime image validation in Laravel 8
body: <p>Laravel version: 8.82.0</p>
  <p>I am uploading an image with inertiajs by making a post request with <code>form.post</code> method. An image data is received in controller as depicted in an image below:</p>
  <p><a href="https://i.stack.imgur.com/pMFTu.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/pMFTu.png" alt="enter image description here" /></a></p>
  <p>My simplified controller:</p>
  <pre><code>public function store(){
      
      Request()-&gt;validate([
          'thumbnail' =&gt; 'required|mimes:png,jpeg,jpg|max:2048'
  
          // Also tried, still fails.
          // 'thumbnail' =&gt; 'required|image|mimes:png,jpeg,jpg|max:2048'
  
      ]);
      
      return Redirect::route('showcases.index');
  
  }
  </code></pre>
  <p>Upon ariving header content-type is <code>application/json</code>, I tried changing it to <code>multipart/form-data</code> but to no avail, image validation still fails.</p>
  <p>The error I get is: <code>The thumbnail must be a file of type: png, jpeg, jpg</code></p>