return '';
break;
case 'netpbm':
- if (!defined('_PNMSCALE_COMMAND') OR _PNMSCALE_COMMAND=='')
+ if (defined('_PNMSCALE_COMMAND') AND _PNMSCALE_COMMAND=='')
return '';
break;
case 'imagick':
return '';
break;
case 'convert':
- if (!defined('_CONVERT_COMMAND') OR _CONVERT_COMMAND=='')
+ if (defined('_CONVERT_COMMAND') AND _CONVERT_COMMAND=='')
return '';
break;
}