<?php?
require_once?'string.func.php';
//通過GD庫做驗證碼
function?verifyImage($type=1,$length=4,$pixel=0,$line=0,$sess_name?=?"verify"){
	session_start();
	//創建畫布
	$width?=?80;
	$height?=?28;
	$image?=?imagecreatetruecolor?(?$width,?$height?);
	$white?=?imagecolorallocate?(?$image,?255,?255,?255?);
	$black?=?imagecolorallocate?(?$image,?0,?0,?0?);
	//用填充矩形填充畫布
	imagefilledrectangle?(?$image,?1,?1,?$width?-?2,?$height?-?2,?$white?);
	$chars?=?buildRandomString?(?$type,?$length?);
	$_SESSION?[$sess_name]?=?$chars;
	//$fontfiles?=?array?("msyh.ttf",?"msyhbd.ttf",?"simkai.ttf",?"SIMLI.TTF",?"simsun.ttc",?"SIMYOU.TTF"?);
	$fontfiles?=?array?("SIMYOU.TTF"?);
	//由于字體文件比較大，就只保留一個字體，如果有需要的同學可以自己添加字體，字體在你的電腦中的fonts文件夾里有，直接運行輸入fonts就能看到相應字體
	for($i?=?0;?$i?<?$length;?$i?++)?{
		$size?=?mt_rand?(?14,?18?);
		$angle?=?mt_rand?(?-?15,?15?);
		$x?=?5?+?$i?*?$size;
		$y?=?mt_rand?(?20,?26?);
		$fontfile?=?"../fonts/"?.?$fontfiles?[mt_rand?(?0,?count?(?$fontfiles?)?-?1?)];
		$color?=?imagecolorallocate?(?$image,?mt_rand?(?50,?90?),?mt_rand?(?80,?200?),?mt_rand?(?90,?180?)?);
		$text?=?substr?(?$chars,?$i,?1?);
		imagettftext?(?$image,?$size,?$angle,?$x,?$y,?$color,?$fontfile,?$text?);
	}
	if?($pixel)?{
		for($i?=?0;?$i?<?50;?$i?++)?{
			imagesetpixel?(?$image,?mt_rand?(?0,?$width?-?1?),?mt_rand?(?0,?$height?-?1?),?$black?);
		}
	}
	if?($line)?{
		for($i?=?1;?$i?<?$line;?$i?++)?{
			$color?=?imagecolorallocate?(?$image,?mt_rand?(?50,?90?),?mt_rand?(?80,?200?),?mt_rand?(?90,?180?)?);
			imageline?(?$image,?mt_rand?(?0,?$width?-?1?),?mt_rand?(?0,?$height?-?1?),?mt_rand?(?0,?$width?-?1?),?mt_rand?(?0,?$height?-?1?),?$color?);
		}
	}
	header?(?"content-type:image/gif"?);
	imagegif?(?$image?);
	imagedestroy?(?$image?);
}

<?php?
/**
?*?生成驗證碼
?*?@param?int?$type
?*?@param?int?$length
?*?@return?string
?*/
function?buildRandomString($type=1,$length=4){
	if?($type?==?1)?{
		$chars?=?join?(?"",?range?(?0,?9?)?);
	}?elseif?($type?==?2)?{
		$chars?=?join?(?"",?array_merge?(?range?(?"a",?"z"?),?range?(?"A",?"Z"?)?)?);
	}?elseif?($type?==?3)?{
		$chars?=?join?(?"",?array_merge?(?range?(?"a",?"z"?),?range?(?"A",?"Z"?),?range?(?0,?9?)?)?);
	}
	if?($length?>?strlen?(?$chars?))?{
		exit?(?"字符串長度不夠"?);
	}
	$chars?=?str_shuffle?(?$chars?);
	return?substr?(?$chars,?0,?$length?);
}

為什么我復制老師的代碼測試不顯示？gd庫也開了

把你的header("Content-type: image/png;")替換成下面三行看看

header("Cache-Control: max-age=1, s-maxage=1, no-cache, must-revalidate");

ob_clean();?

header("Content-type: image/png;charset=utf8");

gd庫有開嗎