ckfinder makes thumbs>Images folder but doesn't make a file

I am running on a Linux server and using PHP with safe mode on. I can upload images just fine, but the thumbnail is not created.

I manually created a thumbs folder, and when I upload an image an Images folder is created inside the thumbs folder, but no thumbnails are created. I've tried with jpg, gif, and png in both Firefox and IE with the same effect.

Here are my config settings - I'm not sure what else to check:

$baseUrl = 'http://domain.com/';
$baseDir = '/var/www/vhosts/domain.com/httpdocs/';

$config['Thumbnails'] = Array(
'url' => $baseUrl . '_thumbs',
'directory' => $baseDir . '_thumbs',
'enabled' => true,
'directAccess' => false,
'maxWidth' => 100,
'maxHeight' => 100,
'bmpSupported' => false,
'quality' => 80);

$config['ResourceType'][] = Array(
'name' => 'Files', // Single quotes not allowed
'url' => $baseUrl . 'uploads',
'directory' => $baseDir . 'uploads',
'maxSize' => 0,
'allowedExtensions' => '7z,aiff,asf,avi,bmp,csv,doc,fla,flv,gif,gz,gzip,jpeg,jpg,mid,mov,mp3,mp4,mpc,mpeg,mpg,ods,odt,pdf,png,ppt,pxd,qt,ram,rar,rm,rmi,rmvb,rtf,sdc,sitd,swf,sxc,sxw,tar,tgz,tif,tiff,txt,vsd,wav,wma,wmv,xls,zip',
'deniedExtensions' => '');

$config['ResourceType'][] = Array(
'name' => 'Images',
'url' => $baseUrl . 'ccimg',
'directory' => $baseDir . 'ccimg',
'maxSize' => 0,
'allowedExtensions' => 'bmp,gif,jpeg,jpg,png',
'deniedExtensions' => '');

$config['ResourceType'][] = Array(
'name' => 'Flash',
'url' => $baseUrl . 'ccimg',
'directory' => $baseDir . 'ccimg',
'maxSize' => 0,
'allowedExtensions' => 'swf,flv',
'deniedExtensions' => '');

Thanks in advance for any suggestions!

TH