<?php

    header("content-type:image/png");

    $width = 500;

    $height = 500;

    $img = imagecreatetruecolor($width, $height);

    $string = "hello";

    //7种颜色，存入数组

    $red = imagecolorallocate($img, 255, 0, 0);

    $white = imagecolorallocate($img, 255, 255, 255);

    $green = imagecolorallocate($img, 0, 255, 0);

    $blue = imagecolorallocate($img, 0, 0, 255);

    $aaa = imagecolorallocate($img, 255, 255, 0);

    $bbb = imagecolorallocate($img, 0, 255, 255);

    $ccc = imagecolorallocate($img, 255, 0, 255);

    $colors = array($white,$red,$green,$blue,$aaa,$bbb,$ccc);

    //画点

    for ($i=0; $i < 1000; $i++) {

       imagesetpixel($img, mt_rand(0,$width), mt_rand(0,$height), $colors[mt_rand(0,6)]);

    }

    //划线

    for ($i=0; $i < 200; $i++) {

       imageline($img, mt_rand(0,$width), mt_rand(0,$height), mt_rand(0,$width), mt_rand(0,$height), $colors[mt_rand(0,6)]);

    }

    //生成4位验证码

    $a1 = range(0, 9);

    $a2 = range(a, z);

    $a3 = range(A, Z);

    $a4 = array_merge($a1,$a2,$a3);

    $num = 4;

    $fontsize = 60;

    for ($i=0; $i < 4; $i++) {

       imagettftext($img, $fontsize, mt_rand(-45,45), $width/$num*$i+$fontsize, $height/2, $colors[mt_rand(0,6)], "Fonts/msyh.ttf", $a4[mt_rand(0,61)]);

    }

    imagepng($img);

  ?>

 <?php

    header("content-type:image/png");

    $width = 110;

    $height = 40;

    $img = imagecreatetruecolor($width, $height);

    $string = "hello";

    //7种颜色，存入数组

    $red = imagecolorallocate($img, 255, 0, 0);

    $white = imagecolorallocate($img, 255, 255, 255);

    $green = imagecolorallocate($img, 0, 255, 0);

    $blue = imagecolorallocate($img, 0, 0, 255);

    $aaa = imagecolorallocate($img, 255, 255, 0);

    $bbb = imagecolorallocate($img, 0, 255, 255);

    $ccc = imagecolorallocate($img, 255, 0, 255);

    $colors = array($white,$red,$green,$blue,$aaa,$bbb,$ccc);

    //画点

    for ($i=0; $i < 10; $i++) {

       imagesetpixel($img, mt_rand(0,$width), mt_rand(0,$height), $colors[mt_rand(0,6)]);

    }

    //划线

    for ($i=0; $i < 4; $i++) {

       imageline($img, mt_rand(0,$width), mt_rand(0,$height), mt_rand(0,$width), mt_rand(0,$height), $colors[mt_rand(0,6)]);

    }

    //生成4位验证码

    $a1 = range(0, 9);

    $a2 = range(a, z);

    $a3 = range(A, Z);

    $a4 = array_merge($a1,$a2,$a3);

    $num = 4;

    $fontsize = 20;

    for ($i=0; $i < 4; $i++) {

       imagettftext($img, $fontsize, mt_rand(-45,45), $width/$num*$i+5, 30, $colors[mt_rand(0,6)], "Fonts/msyh.ttf", $a4[mt_rand(0,61)]);

    }

    imagepng($img);

  ?>