有错误出现求解答

/*图片压缩*/
public function thumbImage($width,$height){
   $image_thumb=imagecreatetruecolor($width,$height);
   imagecopyresampled($image_thumb,$this->image,0,0,0,0,$width,$height,$this->imageinfo['width'],$this->imageinfo['height']);
   imagedestroy($this->image);
   $this->image=$image_thumb;
}
/*添加文字水印*/
public function fontMark($content,$font_url,$font_size,$color,$local,$angle){
   $colortrue=imagecolorallocatealpha($this->image,$color[0],$color[1].$color[2],$color[3]);
   imagettftext($this->image,$font_size,$angle,$local['x'],$local['y'],$colortrue,$font_url,$content);
}
/*浏览器中显示图片*/
public function showImage(){
   header("Content-type:",$this->imageinfo['mime']);
   self::printImage($this->image);
}
/*保存实体文件*/
public function saveImage($picName){
   $picturename=$picName.'.'.$this->imageinfo['type'];
   self::printImage($this->image,$picturename);
}