图片上传，文件名存入数据库代码

要求对代码有详细的教程，谢谢！
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if($_FILES['upfile']['size'] == 0){
echo "请选择需要上传的图片";
exit;
}else{
$imageinfo=getimagesize($_FILES['upfile']['tmp_name']);
if($imageinfo[0] > 120 or $imageinfo[1] > 80){
echo "图片大小不符合标准";
exit;
}elseif($imageinfo[2] < 1 or $imageinfo[2] > 3){
echo "简介图片只能是GIF,JPG,PNG格式";
exit;
}
if($imageinfo[2] == 1){
$imageinfo[2] = ".gif";
}elseif($imageinfo[2] == 2){
$imageinfo[2] = ".jpg";
}else{
$imageinfo[2] = ".png";
}
$imgname = date(YmdHis).substr(md5($fname),0,5).$imageinfo[2];
copy($_FILES['upfile']['tmp_name'], "$root/$set[flashimgdir]/$imgname");
}