If you look at you file class, you can see this function.
You can redefine you image thumb size there.
public static function returnFile($mode = null)
{
$jinput = JFactory::getApplication()->input;
$path = $jinput->get('path', null, 'STRING');
$size = $jinput->get('size', null, 'CMD');
$action = $jinput->get('action', null, 'CMD');
$attrs = $jinput->get('attrs', null, 'STRING');
$filePath = null;
if (!$path)
{
// Read through database index
$view = $jinput->get('view', null, 'CMD');
$key = $jinput->get('key', null, 'CMD');
$cid = $jinput->get('cid', null, 'INT');
if ($view && $key && $cid)
$path = self::getFromIndex($view, $key, $cid);
//Fallback
if (!$path)
$filePath = DEMO120_IMAGES_FALLBACK_ROOT .DS. DEMO120_IMAGES_FALLBACK_NAME;
}
$options = null;
if (!$filePath && $path)
$filePath = self::getPhysical($path, $options);
$ext = self::getExt($filePath);
jimport('joomla.filesystem.file');
$imagesExt = array('jpg', 'jpeg', 'gif', 'png', 'bmp');
$mime = null;
if ($action == 'download')
$mime = 'application/force-download'; // OU application/octet-stream
else if (self::exists($filePath))
$mime = self::getMime($filePath);
//Is image ?
if (($action != 'download') &&
(in_array($ext, $imagesExt) //Check on extension
|| ($mime && preg_match("/^image/", $mime))) //Check on mime
)
{
require_once(JPATH_ADMIN_DEMO120 .DS. 'classes' .DS. 'images.php');
$thumb = new Demo120Images($filePath, $mime);
if ($attrs)
$thumb->attrs($attrs);
if ($size && preg_match("/([0-9]+)x([0-9]+)/", $size, $matches))
{
$thumb->width($matches[1]);
$thumb->height($matches[2]);;
}
$thumb->get();
exit();
}
else if (!JFile::exists($filePath))
{
$app = JFactory::getApplication();
$msg = JText::sprintf( "DEMO120_UPLOAD_FILE_NOT_FOUND", $path);
$app->enqueueMessage($msg, 'error');
jexit();
}
//Non image and non outputable mimes : Force download
if (!in_array($mime, array(
'application/x-shockwave-flash'
)))
{
header('Content-Description: File Transfer');
header("Content-Disposition: attachment; filename=\"".basename($filePath) . "\"");
}
//Read and return file contents with original mime header
header('Content-Type: ' . $mime);
header('Content-Transfer-Encoding: binary');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header('Content-Length: ' . filesize($filePath));
ob_clean();
flush();
readfile($filePath);
jexit();
}
EDIT :
Here
