php GD库生成缩略图分享一个利用php GD库生成缩略图的例子。php利用GD库生成缩略图。代码:<formmethod="post"action="suo_do.php"enctype="multipart/form-data"><inputtype="file"name="pic"/><inputtype="submit"value="上传1"/></form><?phpheader("content-type:text/html;charset=gbk");ini_set("date.timezone","Asia/chong");//判断文件是否为空if(empty($_FILES)){echo"上传文件过大";exit;}//判断文件上传是否有错误if($_FILES['pic']['error']){echo"上传文件";exit;}//判断文件类型是否非法获取文件后缀$allowtype=array("jpg","png","jpeg","gif");$a=explode('.',$_FILES['pic']['name']);$index=count($a)-1;$ex=strtolower($a[$index]);if(!in_array($ex,$allowtype)){echo"上传文件非法";exit;}$file=date('YmdHis').rand().".".$ex;$src=$_FILES['pic']['tmp_name'];$des="upload/".$file;$rs=move_uploaded_file($src,$des);//缩略图//读取已经上传图片$image=imagecreatefromjpeg($des);$a=getimagesize($des);$w=$a[0];$h=$a[1];if($w>$h){$width=300;$height=$width/$w*$h;}elseif($w<$h){$height=300;$width=$height/$h*$w;}else{$width=300;$height=300;}www.jbxue.com//创建空白新图片$newimage=imagecreatetruecolor($width,$height);//copy源图片内容copy新图片imagecopyresized($newimage,$image,0,0,0,0,$width,$height,$w,$h);$filename="upload/s_".$file;imagejpeg($newimage,$filename);