[Typo3] gamma-correction in own Extension

[Georg Ringer]

Hi Peter,
> You need to create your IMAGE as a GIFBUILDER object.. (More or less the 
> same way you already create the IMAGE, except it needs *several* more 
> parameters..)

I tried but i only get a white image :/
my Code:
   $itc = Array();
   $itc['file'] = 'GIFBUILDER';
   $itc['file.']['10'] = 'IMAGE';
   $itc['file.']['10.']['file'] = 'uploads/tx_rgwallpapermodern/'. 
$row['image'];
   $itc['file.']['10.']['file']['maxW'] = 400;
   $itc['file.']['10.']['file']['maxH'] = 300;
   $itc['file.']['20'] = 'EFFECT';
   $itc['file.']['20.']['value'] = 'gamma=3';
   $markerArray['###SINGLE_IMAGE###'] = $this->cObj->IMAGE($itc);

No matter if i use the settings with ['20'] or not.
Can you please give me another hint?

thanks a lot!!
Georg