[Typo3] gamma-correction in own Extension

[Georg Ringer]

Hi,

I'm getting an image out of the DB and making this
   $imgTSConfig = Array();
   $imgTSConfig['file'] = 'uploads/tx_rgwallpapermodern/'. $row['image'];
   $imgTSConfig['file.']['maxW'] = $this->config['widthLarge'];
   $imgTSConfig['file.']['maxH'] = $this->config['heightLarge'];
   $imgTSConfig['altText'] = $row['title'];
   $imgTSConfig['titleText'] = $row['title'];
   $markerArray['###SINGLE_IMAGE###'] = $this->cObj->IMAGE($imgTSConfig);

Now i want to make a gamma correction with the image (to brighten the image) 
but I have absolutly no clue how do that (without using e.g. CSS)

Many thanks for help!
Georg