index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Photo Gallery</title>
    <link rel="stylesheet" href="style.css">
  </head>
  <body>
    <header class="header">
      <h1>...css flexbox photo gallery...</h1>
    </header>
    <div class="gallery">
        
      <img src="Images/img-1.jpg">
      <img src="Images/img-2.jpg">
      <img src="Images/img-3.jpg">
      <img src="Images/img-4.jpg">
      <img src="Images/img-5.jpg">
      <img src="Images/img-6.jpg">
      <img src="Images/img-7.jpg">
      <img src="Images/img-8.jpg">
      <img src="Images/img-9.jpg">
      <img src="Images/img-10.jpg">
      <img src="Images/img-11.jpg">
      <img src="Images/img-12.jpg">

    </div>
</body>
</html>