Creating black images when trying to create thumbnails

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Hi all,

I am a newbie at this.  I am trying to create thumbnails.  However, I
am only creating black image with the correct thumbnail size.  I am
using php 5.1.6 and GD 2.0.28.  Below is the code that I am using.
Can any one help?




function createThumbnail($imageDirectory, $imageName, $thumbDirectory,
$srcImg = imagecreatefromjpeg("$imageDirectory/$imageName");
$origWidth = imagesx($srcImg);
$origHeight = imagesy($srcImg);

$thumbHeight  0;
$thumbWidth 0;

     if($origWidth > $origHeight && $thumbHeight < $origHeight){
       $thumbHeight = $origHeight / ($origWidth / $thumbWidth);
     } else if ($origWidth < $origHeight && $thumbWidth < $origWidth)
       $thumbWidth = $origWidth / ($origHeight / $thumbHeight);
     } else {
       $thumbWidth = $origWidth;
       $thumbHeight = $origHeight;
    $thumbImg = imagecreatetruecolor($thumbWidth, $thumbHeight);

    imagecopyresampled($thumbImg, $srcImg, 0, 0, 0, 0, $thumbWidth,
$thumbHeight, origWidth, $origHeight);

    imagejpeg($thumbImg, "$thumbDirectory/$imageName");

        if(!mkdir("/home/alanna/public_html/pics/thumb/"))    {
            echo "error making thumbs directory";

    if(file_exists("/home/alanna/public_html/pics/thumb/". $imagename)){
        echo "File already exists";

    createThumbnail("/home/alanna/public_html/pics/full/", $imagename, "/
home/alanna/public_html/pics/thumb/", 100);


Re: Creating black images when trying to create thumbnails wrote:

Quoted text here. Click to load it


To debug imagecreationscripts try the following:
1) Set the header for mimetype from image/jpeg (or whatever it is) to  
2) Run your script.

That way your browser can actually display any errors in your script.
If you leave the mimetype to an image, the browser will try to interpret  
your echos as an image, maybe resulting in a black image.

Of course, when you fixed your errors, you can switch back to image/jpeg to  
check if PHP actually delivers an image you like.

Erwin Moller
Erwin Moller

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