php多张图片拼接成一张图片

<?php$imgs    = array();$imgs[0] = 'imgs/1.jpg';$imgs[1] = 'imgs/2.jpg';$imgs[2] = 'imgs/3.jpg';$imgs[3] = 'imgs/4.jpg';$target  = 'emp.jpg'; //背景图片 $target_img = Imagecreatefromjpeg($target); $source = array(); foreach ($imgs as $k => $v) {    $source[$k]['source'] = Imagecreatefromjpeg($v);         $source[$k]['size'] = getimagesize($v);     } //imagecopy ($target_img,$source[0]['source'],2,2,0,0,$source[0]['size'][0],$source[0]['size'][1]);//imagecopy ($target_img,$source[1]['source'],250,2,0,0,$source[1]['size'][0],$source[1]['size'][1]);$num1 = 0;$num  = 1;$tmp  = 2;$tmpy = 2; //图片之间的间距for ($i = 0; $i < 4; $i++) {    imagecopy($target_img, $source[$i]['source'], $tmp, $tmpy, 0, 0, $source[$i]['size'][0], $source[$i]['size'][1]);         $tmp = $tmp + $source[$i]['size'][0];    $tmp = $tmp + 5;    if ($i == $num) {        $tmpy = $tmpy + $source[$i]['size'][1];        $tmpy = $tmpy + 5;        $tmp  = 2;        $num  = $num + 3;    }}Imagejpeg($target_img, 'pin.jpg'); ?><img src="pin.jpg">