自己写的一个图片加水印类，暂时只支持水印图片，水印文字的还没有完善
代码不是很完善，欢迎大家交流指正！
调用方式：
先包含类文件
然后实例化类：
$img = new Images;
然后提供图片：
$img->imgpath(原图片路径及名称，水印图片路径及名称);
之后开始加水印：
$img->send();
说明：
send( strimg filename ) 这个方法有一个函数，可以省略，在省略的情况下，保存的图片路径和名称和原来的一样，如需保存成例外的图片，就在这里提供要保存的图片路径及名称
例外，还有一个方法，show(); 这个方法用于显示加好水印的图片
这个方法可以单独调用，但必须先调用 send()方法， 也可以连续调用： $img->send()->show();

 
<?php
class Images{
     private $imgA = '', $imgB = '';
     private $imgWA = 0, $imgWB = 0, $typea = 0;
     private $imgHA = 0, $imgHB = 0, $typeb = 0;
     private $objecta, $objectb;
     private $weizhi = 1; // 1坐上， 2中上， 3 右上， 4 中左， 5中部， 6 中右， 7， 下左， 8 下中， 9 下右
     private $X = 0, $Y = 0;
     private $okfile = '1.jpg';
      
      
     public function imgpath( $oldimg = '', $newing = '', $WeiZhi = 1 ) { //指定图片
        $this->imgA   = $oldimg;
        $this->imgB   = $newing;
        $this->weizhi = $WeiZhi;
       return $this;
     }
      
     public function send( $Name = '' ){
         !empty( $Name ) or $Name = $this->imgA;
         list($this->imgWA, $this->imgWB, $this->typea) = $this->imgread( $this->imgA );
         list($this->imgHA, $this->imgHB, $this->typeb) = $this->imgread( $this->imgB );
         $this->objecta = $this->openimg( $this->imgA, $this->typea );
         $this->objectb = $this->openimg( $this->imgB, $this->typeb );
         $this->WZ();
         $this->start();
         $this->over( $Name );
         return $this;
     }
     
    private function WZ() {
        switch( $this->weizhi ) {
            case 2:
                 $this->X = ( $this->imgWA - $this->imgHA ) / 2;
                 break;
            case 3:
                 $this->X = ( $this->imgWA - $this->imgHA ); 
                 break;
            case 4:
                 $this->Y = ( $this->imgWB - $this->imgHB ) / 2 ;
                 break;
            case 5:
                 $this->X = ( $this->imgWA - $this->imgHA ) / 2;
                 $this->Y = ( $this->imgWB - $this->imgHB ) / 2 ;
                 break;
            case 6:
                 $this->X = ( $this->imgWA - $this->imgHA );
                 $this->Y = ( $this->imgWB - $this->imgHB ) / 2 ;
                 break;
            case 7:
                 $this->Y = ( $this->imgWB - $this->imgHB );
                 break;
            case 8:
                 $this->X = ( $this->imgWA - $this->imgHA ) / 2;
                 $this->Y = ( $this->imgWB - $this->imgHB );
                 break;
            case 9:
                 $this->X = ( $this->imgWA - $this->imgHA );
                 $this->Y = ( $this->imgWB - $this->imgHB );
                 break;
            default:
                $this->X = 0;
                $this->Y = 0;
        }
    }
     
    private function openimg( $FileName = '', $type = 0 ) {
        switch( $type ) {
            case 1:
                 $obj = imagecreatefromgif( $FileName ); break;
            case 2:
                 $obj = imagecreatefromjpeg( $FileName ); break;
            case 3:
                 $obj = imagecreatefrompng( $FileName ); break;
            default:
                return false;
        }
       return $obj;
    }
     
    private function start(){
        imagecopy( $this->objecta, $this->objectb, $this->X, $this->Y, 0, 0, $this->imgHA, $this->imgHB );
    }
     
    private function over( $name = '1.jpg' ) {
        $this->okfile = $name;
        switch ( $this->typea ) {
            case 1:
                imagegif( $this->objecta, $name );break;
            case 2:
                imagejpeg( $this->objecta, $name );break;
            case 3:
                imagepng( $this->objecta, $name ); break;
            default:
               return false;
        }
    }
     
     
     
    private function imgread( $FilePath = '' ) {
        $Arr = getimagesize( $FilePath );
        return array( $Arr[0], $Arr[1], $Arr[2] );
    }
     
     
   public function show(){
       @header('content-type:image/*');
       echo @file_get_contents( $this->okfile );
   }
     
}