.gallery img{
  width:100%;
  aspect-ratio: 4 / 5;   /*the aspect ratio(might wanna change later)*/
  object-fit: cover;
  display:block;
  border-radius:12px;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  cursor:pointer;
}

<header role="banner">
  <div class="brand">
    <div class="logomark">JL</div>
    <div style="line-height:1">
      <div style="font-weight:700">Alexander Archives</div>
      <div style="font-size:12px;color:var(--muted)">Portfolio Gallery</div>
    </div>
  </div>
  <nav>
    <a href="index.html">Home Page</a>
  </nav>
</header>