PHP支持多种格式图片上传(支持jpg、png、gif)_php技巧

此处一次支持上传2个图片，上传后生成原图和质量较差的图，原图用于保存质量高的图片，质量差的图用于网页显示。
PHP Code

复制代码 代码如下:

<?php
include_once("db.php");
include_once("dbinfo.php");
$connector = new nmdb($host, $username, $password);
$connector -> select_db($database);
$work_group = check_input($_POST['work_group']);
$name = check_input($_POST['name']);
$tel = check_input($_POST['tel']);
$id_card = check_input($_POST['id_card']);
$work_name = check_input($_POST['work_name']);
$place = check_input($_POST['place']);
$work1 = check_input($_POST['work1']);
date_default_timezone_set('PRC');
$date = date("Y-m-d H:i:s");
$quality = 100;
$quality2 = 70;
$quality_png = 9;
$quality2_png = 7;
if(isset($_FILES['work1']) && $_FILES['work1']['error']==0)
{
$size = getimagesize($_FILES['work1']['tmp_name']);
$original = $_FILES['work1']['tmp_name'];
$type = $_FILES['work1']['type'];
//echo $type;
$target_name = date('YmdHis').'_'.preg_replace('`[^a-z0-9-_.]`i','',$_FILES['work1']['name']);
$work1 = $target_name;
$target = dirname(__FILE__).'/uploads/'.$target_name;
switch($type)
{
case "image/jpeg":
$resultImage = imagecreatefromjpeg($original);
imagejpeg($resultImage, $target, $quality);
break;
case "image/png":
$resultImage = imagecreatefrompng($original);
imagepng($resultImage, $target, $quality_png);
break;
case "image/gif":
$resultImage = imagecreatefromgif($original);
imagegif($resultImage, $target, $quality);
break;
default :
die("不支持此文件类型");
exit;
}
$work1_small = $target_name;
$target = dirname(__FILE__).'/uploads/small/'.$target_name;
switch($type)
{
case "image/jpeg":
$resultImage = imagecreatefromjpeg($original);
imagejpeg($resultImage, $target, $quality2);
break;
case "image/png":
$resultImage = imagecreatefrompng($original);
imagepng($resultImage, $target, $quality2_png);
break;
case "image/gif":
$resultImage = imagecreatefromgif($original);
imagegif($resultImage, $target, $quality2);
break;
default :
die("不支持此文件类型");
exit;
}
}
if(isset($_FILES['work2']) && $_FILES['work2']['error']==0)
{
$size = getimagesize($_FILES['work2']['tmp_name']);
$original = $_FILES['work2']['tmp_name'];
$type = $_FILES['work2']['type'];
$target_name = date('YmdHis').'_'.preg_replace('`[^a-z0-9-_.]`i','',$_FILES['work2']['name']);
$work2 = $target_name;
$target = dirname(__FILE__).'/uploads/'.$target_name;
switch($type)
{
case "image/jpeg":
$resultImage = imagecreatefromjpeg($original);
imagejpeg($resultImage, $target, $quality);
break;
case "image/png":
$resultImage = imagecreatefrompng($original);
imagepng($resultImage, $target, $quality_png);
break;
case "image/gif":
$resultImage = imagecreatefromgif($original);
imagegif($resultImage, $target, $quality);
break;
default :
die("不支持此文件类型");
exit;
}
$work2_small = $target_name;
$target = dirname(__FILE__).'/uploads/small/'.$target_name;
switch($type)
{
case "image/jpeg":
$resultImage = imagecreatefromjpeg($original);
imagejpeg($resultImage, $target, $quality2);
break;
case "image/png":
$resultImage = imagecreatefrompng($original);
imagepng($resultImage, $target, $quality2_png);
break;
case "image/gif":
$resultImage = imagecreatefromgif($original);
imagegif($resultImage, $target, $quality2);
break;
default :
die("不支持此文件类型");
exit;
}
}
$sql="insert into photo(work_group,name,tel,id_card,work_name,place,work,work_small,date) values('$work_group','$name','$tel','$id_card','$work_name','$place','$work1','$work1_small','$date')";
//echo $sql;
$result = $connector -> query($sql) or die(mysql_error());
if($work2 != "" && $work2_small != null)
{
$sql2="insert into photo(work_group,name,tel,id_card,work_name,place,work,work_small,date) values('$work_group','$name','$tel','$id_card','$work_name','$place','$work2','$work2_small','$date')";
$result2 = $connector -> query($sql2) or die(mysql_error());
}
$connector -> close($connector);
$page="../upload.php";
echo "<script>alert('上传成功！'); window.location = \"".$page."\";</script>";
?>

有些问题需要说明下：
JPEG图像生成的图像的质量的是一个范围从0（最低质量，最小的文件大小）到100（最高质量，最大文件大小）。而ImagePNG生成图像的质量范围从0到9的，传入的这个范围以外的参数则该函数不会工作。
判断上传文件的类型，$type = $_FILES['work1']['type'];。
创建各种格式的图片可以使用这些函数：imagecreatefromjpeg()、imagecreatefrompng()、imagecreatefromgif()。