简单的php图片上传实例代码

简单防止重名和格式检查的php图片上传实例，含图片格式验证、防止文件重名被覆盖等。

图片上传页面前端代码：

<form name="form1" method="post" action="admin_upfile.php" enctype="multipart/form-data">
<input type="file" name="pic">
<input type="submit" name="Submit" value="开始上传" class="button">
</form>

服务器端，后台页面处理代码：

<?php
//这里上传 $upsize判断上传文件的大小
$uppath = "./upfiles/"; //文件上传路径
//转换根目录的路径
if (strpos($uppath, "/") == 0)
{
$i = 0;
$thpath = $_SERVER["SCRIPT_NAME"];
$thpath = substr($thpath, 1, strlen($thpath));
while (strripos($thpath, "/") !== false)
{
$thpath = substr($thpath, strpos($thpath, "/") + 1, strlen($thpath));
$i = ++$i;
}
$pp = "";
for ($j = 0; $j < $i; ++$j)
{
$pp .= "../";
}
$uppaths = $pp . substr($uppath, 1, strlen($thpath));
}
$filename = date("y-m-d");
if (is_dir($uppaths . $filename) != TRUE)
mkdir($uppaths . $filename, 0777);
$f = $_FILES['pic'];
if ($f["type"] != "image/gif" && $f["type"] != "image/pjpeg" && $f["type"] != "image/jpeg" && $f["type"] != "image/x-png")
{
echo "<script>alert('只能上传图片格式的文件');window.close()</script>";
return false;
}
//获得文件扩展名
$temp_arr = explode(".", $f["name"]);
$file_ext = array_pop($temp_arr);
$file_ext = trim($file_ext);
$file_ext = strtolower($file_ext);
//新文件名
$new_file_name = md5(date("YmdHis")) . '.' . $file_ext;
echo $dest = $uppaths . $filename . "/" . date("ymdhis") . "_" . 
$new_file_name; //设置文件名为日期加上文件名避免重复 上传目录
echo $dest1 = $uppath . $filename . "/" . date("ymdhis") . "_" . 
$new_file_name; //设置文件名为日期加上文件名避免重复
$r = move_uploaded_file($f['tmp_name'], $dest);
?>