合并在PHP两个图像（不同尺寸）

我发现这个脚本在PHP合并两个图像（保持透明）：合并在PHP两个图像（不同尺寸）

function imagecopymerge_alpha($dst_im, $src_im, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h, $pct, $trans = NULL) 
{ 
    $dst_w = imagesx($dst_im); 
    $dst_h = imagesy($dst_im); 

    // bounds checking 
    $src_x = max($src_x, 0); 
    $src_y = max($src_y, 0); 
    $dst_x = max($dst_x, 0); 
    $dst_y = max($dst_y, 0); 
    if ($dst_x + $src_w > $dst_w) 
    $src_w = $dst_w - $dst_x; 
    if ($dst_y + $src_h > $dst_h) 
    $src_h = $dst_h - $dst_y; 

    for($x_offset = 0; $x_offset < $src_w; $x_offset++) 
    for($y_offset = 0; $y_offset < $src_h; $y_offset++) 
    { 
     // get source & dest color 
     $srccolor = imagecolorsforindex($src_im, imagecolorat($src_im, $src_x + $x_offset, $src_y + $y_offset)); 
     $dstcolor = imagecolorsforindex($dst_im, imagecolorat($dst_im, $dst_x + $x_offset, $dst_y + $y_offset)); 

     // apply transparency 
     if (is_null($trans) || ($srccolor !== $trans)) 
     { 
     $src_a = $srccolor['alpha'] * $pct/100; 
     // blend 
     $src_a = 127 - $src_a; 
     $dst_a = 127 - $dstcolor['alpha']; 
     $dst_r = ($srccolor['red'] * $src_a + $dstcolor['red'] * $dst_a * (127 - $src_a)/127)/127; 
     $dst_g = ($srccolor['green'] * $src_a + $dstcolor['green'] * $dst_a * (127 - $src_a)/127)/127; 
     $dst_b = ($srccolor['blue'] * $src_a + $dstcolor['blue'] * $dst_a * (127 - $src_a)/127)/127; 
     $dst_a = 127 - ($src_a + $dst_a * (127 - $src_a)/127); 
     $color = imagecolorallocatealpha($dst_im, $dst_r, $dst_g, $dst_b, $dst_a); 
     // paint 
     if (!imagesetpixel($dst_im, $dst_x + $x_offset, $dst_y + $y_offset, $color)) 
      return false; 
     imagecolordeallocate($dst_im, $color); 
     } 
    } 
    return true; 
}

它工作正常，但不是当我做了一下调整的：

header('Content-Type: image/png'); 

// Get image for the watermark 
$smallImageFilename = 'http://ing0.net/watermark.png'; 
list($oldwidthSmall, $oldheightSmall) = getimagesize($smallImageFilename); 
$newwidthSmall = $newheightSmall = 50; 
$thumb = imagecreatetruecolor($newwidthSmall, $newheightSmall); 
$source = imagecreatefrompng($smallImageFilename); 
imagecopyresized($thumb, $source, 0, 0, 0, 0, $newwidthSmall, $newheightSmall, $oldwidthSmall, $oldheightSmall); 

// Create watermark img 
$watermark = imagecreatetruecolor(50, 50); 
$outImage = imagecreatefrompng('http://ing0.net/image.png');  
$marge_right = 10; 
$marge_bottom = 10; 
$sx = imagesx($watermark); 
$sy = imagesy($watermark); 

imagecopymerge_alpha($outImage, $thumb, imagesx($outImage) - $sx - $marge_right, imagesy($outImage) - $sy - $marge_bottom, 0, 0, imagesx($thumb), imagesy($thumb), 100); 

imagepng($outImage); 
imagedestroy($outImage);

当我这样做透明度不会发生，任何人都看到我要去哪里错了？

编辑：

在它上面的代码利用这些图像：