title: Why transparent background doesn't work with GD?
body: <p>I'm creating image with PHP library GD:</p>
  
  <pre><code>$image = imagecreatefrompng('http://polariton.ad-l.ink/8rRSf4CpN/thumb.png');
  $w = imagesx($image);
  $h = imagesy($image);
  
  $border = imagecreatefrompng('https://www.w3schools.com/css/border.png');
  
  // New border width
  
  $x1 = $w;
  $x2 = 28;
  $x3 = (int)($x1 / $x2);
  $x4 = $x1 - $x3 * $x2;
  $x5 = $x4 / $x3;
  $x2 = $x2 + $x5;
  
  $bw = $x2;
  
  // New border height
  
  $y1 = $h;
  $y2 = 28;
  $y3 = (int)($y1 / $y2);
  $y4 = $y1 - $y3 * $y2;
  $y5 = $y4 / $y3;
  $y2 = $y2 + $y5;
  
  $bh = $y2;
  
  // New image width and height
  
  $newWidth = (int)$w * (1 - ((($bw * 100) / (int)$w) / 100 * 2));
  $newHeight = (int)$h * (1 - ((($bh * 100) / (int)$h) / 100 * 2));
  
  // Transparent border
  
  $indent = imagecreatetruecolor($w, $h);
  $color = imagecolorallocatealpha($indent, 0, 0, 0, 127);
  imagefill($indent, 0, 0, $color);
  
  imagecopyresampled($indent, $image, $bw, $bw, 0, 0, $newWidth, $newHeight, $w, $h);
  
  // Vertical border
  
  $verticalX = 0;
  $verticalY = $bh;
  
  while ($verticalY &lt; $h - $bh) {
      // Left
      imagecopy($indent, $border, $verticalX, $verticalY, 0, 27, $bh, $bh);
  
      // Right
      imagecopy($indent, $border, $w - $bw, $verticalY, 0, 27, $bh, $bh);
  
      $verticalY += $bh;
  }
  
  // Horizontal border
  
  $horizontalX = $bw;
  $horizontalY = 0;
  
  while ($horizontalX &lt; $w - $bw) {
      // Top
      imagecopy($indent, $border, $horizontalX, $horizontalY, 0, 27, $bw, $bw);
  
      // Bottom
      imagecopy($indent, $border, $horizontalX, $h - $bh, 0, 27, $bw, $bw);
  
      $horizontalX += $bw;
  }
  
  // Left top border
  imagecopy($indent, $border, 0, 0, 0, 0, $bw, $bh);
  
  // Right top border
  imagecopy($indent, $border, $w - $bw, 0, 0, 0, $bw, $bh);
  
  // Right bottom border
  imagecopy($indent, $border, $w - $bw, $h - $bh, 0, 0, $bw, $bh);
  
  // Left bottom border
  imagecopy($indent, $border, 0, $h - $bh, 0, 0, $bw, $bh);
  
  
  // Save result
  
  header('Content-Type: image/png');
  imagepng($indent);
  </code></pre>
  
  <p>But transparency does't work:
  <a href="https://i.stack.imgur.com/SatTq.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SatTq.png" alt="enter image description here"></a></p>
  
  <p>Idk why, I do everything as written in the documentation.</p>
  
  <p>What could be the problem?</p>