php中制作缩略图的方法也很简单，是用imagecopyresampled方法根据源图制作一个小一点的图片，来看代码check_image_addthumbs.php
<?php
//修改图片效果
$db = mysql_connect(‘localhost‘,‘root‘,‘Ctrip07185419‘) or die(‘can not connect to database‘);
mysql_select_db(‘moviesite‘,$db) or die(mysql_error($db));
//上传文件的路径
$dir = ‘D:\Serious\phpdev\test\images‘;
//缩略图的路径
$thumbdir = ‘D:\Serious\phpdev\test\images\thumbs‘;
//设置环境变量
putenv(‘GDFONTPATH=‘.‘C:\Windows\Fonts‘);
$font = "arial";//upload_image.php页面传递过来的参数，如果是上传图片
if($_POST[‘submit‘] == ‘Upload‘)
{
if($_FILES[‘uploadfile‘][‘error‘] != UPLOAD_ERR_OK)
{
switch($_FILES[‘uploadfile‘][‘error‘])
{
case UPLOAD_ERR_INI_SIZE:
die(‘The uploaded file exceeds the upload_max_filesize directive‘);
break;
case UPLOAD_ERR_FORM_SIZE:
die(‘The upload file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form‘);
break;
case UPLOAD_ERR_PARTIAL:
die(‘The uploaded file was only partially uploaded‘);
break;
case UPLOAD_ERR_NO_FILE:
die(‘No file was uploaded‘);
break;
case UPLOAD_ERR_NO_TMP_DIR:
die(‘The server is missing a temporary folder‘);
break;
case UPLOAD_ERR_CANT_WRITE:
die(‘The server fail to write the uploaded file to the disk‘);
break;
case UPLOAD_ERR_EXTENSION:
die(‘The upload stopped by extension‘);
break;
}
}
$image_caption = $_POST[‘caption‘];
$image_username = $_POST[‘username‘];
$image_date = date(‘Y-m-d‘);
list($width,$height,$type,$attr) = getimagesize($_FILES[‘uploadfile‘][‘tmp_name‘]);
$error = ‘The file you upload is not a supported filetype‘;
switch($type)
{
case IMAGETYPE_GIF:
$image = imagecreatefromgif($_FILES[‘uploadfile‘][‘tmp_name‘]) or die($error);
break;
case IMAGETYPE_JPEG:
$image = imagecreatefromjpeg($_FILES[‘uploadfile‘][‘tmp_name‘]) or die($error);
break;
case IMAGETYPE_PNG:
$image = imagecreatefrompng($_FILES[‘uploadfile‘][‘tmp_name‘]) or die($error);
break;
default:
break;
}
$query = ‘insert into images(image_caption,image_username,image_date) values("‘.$image_caption.‘" , "‘.$image_username.‘","‘.$image_date.‘")‘;
$result = mysql_query($query,$db) or die(mysql_error($db));
$last_id = mysql_insert_id();// $imagename = $last_id.‘.jpg‘;
// imagejpeg($image,$dir.‘/‘.$imagename);
// imagedestroy($image);$image_id = $last_id;
imagejpeg($image , $dir.‘/‘.$image_id.‘.jpg‘);
imagedestroy($image);
}
else //如果图片已经上传，则从数据库中取图片名字
{
$query = ‘select image_id,image_caption,image_username,image_date from images where image_id=‘.$_POST[‘id‘];
$result = mysql_query($query,$db) or die(mysql_error($db));
extract(mysql_fetch_assoc($result));
list($width,$height,$type,$attr) = getimagesize($dir.‘/‘.$image_id.‘.jpg‘);
}//如果是保存图片
if($_POST[‘submit‘] == ‘Save‘)
{
if(isset($_POST[‘id‘]) && ctype_digit($_POST[‘id‘]) && file_exists($dir.‘/‘.$_POST[‘id‘].‘.jpg‘))
{
$image = imagecreatefromjpeg($dir.‘/‘.$_POST[‘id‘].‘.jpg‘);
}
else
{
die(‘invalid image specified‘);
}
$effect = (isset($_POST[‘effect‘])) ? $_POST[‘effect‘] : -1;
switch($effect)
{
case IMG_FILTER_NEGATE:
imagefilter($image , IMG_FILTER_NEGATE); //将图像中所有颜色反转
break;
case IMG_FILTER_GRAYSCALE:
imagefilter($image , IMG_FILTER_GRAYSCALE); //将图像转换为灰度的
break;
case IMG_FILTER_EMBOSS:
imagefilter($image , IMG_FILTER_EMBOSS); //使图像浮雕化
break;
case IMG_FILTER_GAUSSIAN_BLUR:
imagefilter($image , IMG_FILTER_GAUSSIAN_BLUR); //用高斯算法模糊图像
break;
}if(isset($_POST[‘emb_caption‘]))
{
imagettftext($image , 12 , 0 , 20 , 20 , 0 , $font , $image_caption);
}$thumb_width = $width * 0.10;
$thumb_height = $height * 0.10;//创建一个缩略图
$thumb = imagecreatetruecolor($thumb_width, $thumb_height);
imagecopyresampled($thumb, $image, 0, 0, 0, 0, $thumb_width, $thumb_height, $width, $height);
//保存原图
imagejpeg($image, $dir . ‘/‘ . $_POST[‘id‘] . ‘.jpg‘, 100);
//保存缩略图
imagejpeg($thumb, $thumbdir . ‘/‘ . $_POST[‘id‘] . ‘.jpg‘, 100);
imagedestroy($thumb);
?>
<html>
<head>
<title>Here is your pic!</title>
</head>
<body>
<h1>Your image has been saved!</h1>
<img src="images/<?php echo $_POST[‘id‘];?>.jpg" />
</body>
</html>
<?php
}
else
{
?>
<html>
<head>
<title>Here is your pic!</title>
</head>
<body>
<h1>So how does it feel to be famous?</h1>
<p>Here is the picture you just uploaded to your servers:</p>
<!--<img src="images/<?php echo $imagename;?>" style="float:left;" />-->
</body>
</html>
<?php
if($_POST[‘submit‘] == ‘Upload‘)
{
$imagename = ‘images/‘.$image_id.‘.jpg‘;
}
else
{
$imagename = ‘image_effect.php?id=‘.$image_id.‘&e=‘.$_POST[‘effect‘];
if(isset($_POST[‘emb_caption‘]))
{
$imagename .= ‘&capt=‘.urlencode($image_caption);
}
}
?>
<img src="<?php echo $imagename;?>" style="float:left;" />
<table>
<tr>
<td>Image save as:</td>
<td><?php $image_id?></td>
</tr>
<tr>
<td>Height:</td>
<td><?php echo $height;?></td>
</tr>
<tr>
<td>Widht:</td>
<td><?php echo $width;?></td>
</tr>
<tr>
<td>Upload date:</td>
<td><?php echo $image_date;?></td>
</tr>
</table>
<p>You may apply a special effect to your image from the list of option below.
Note:saving an image with any of the filters applied <em>can be undone</em>
</p>
<form action="<?php echo $_SERVER[‘PHP_SELF‘];?>" method="post">
<div>
<input type="hidden" name="id" value="<?php echo $image_id;?>"/>
Filter:<select name="effect" id="">
<option value="-1">None</option>
<?php
echo ‘<option value="‘.IMG_FILTER_GRAYSCALE.‘" ‘;
if(isset($_POST[‘effect‘]) && $_POST[‘effect‘] == IMG_FILTER_GRAYSCALE)
{
echo ‘selected="selected"‘;
}
echo ‘ >Black and white</option>‘;echo ‘<option value="‘.IMG_FILTER_GAUSSIAN_BLUR.‘"‘;
if(isset($_POST[‘effect‘]) && $_POST[‘effect‘] == IMG_FILTER_GAUSSIAN_BLUR)
{
echo ‘ selected="selected"‘;
}
echo ‘>Blur</option>‘;echo ‘<option value="‘.IMG_FILTER_EMBOSS.‘"‘;
if(isset($_POST[‘effect‘]) && $_POST[‘effect‘] == IMG_FILTER_EMBOSS)
{
echo ‘selected="selected"‘;
}
echo ‘>Emboss</option>‘;echo ‘<option value="‘.IMG_FILTER_NEGATE.‘"‘;
if(isset($_POST[‘effect‘]) && $_POST[‘effect‘] == IMG_FILTER_NEGATE)
{
echo ‘selected="selected"‘;
}
echo ‘>Negative</option>‘;
?>
</select><br />
<?php
echo ‘<input type="checkbox" name="emb_caption"‘;
if(isset($_POST[‘emb_caption‘]))
{
echo ‘ checked="checked"‘;
}
echo ‘ />Embed caption in image?‘;
?>
<input type="submit" value="Preview" name="submit" /><br /><br />
<input type="submit" value="Save" name="submit" /></div>
</form>
<?php
}
?>
缩略图放在D:\Serious\phpdev\test\images\thumbs路径下面，这里我们添加了一个gallery.php文件来陈列所有的缩略图，代码如下：
<?php
$db = mysql_connect(‘localhost‘,‘root‘,‘Ctrip07185419‘) or die(‘can not connect to database‘);
mysql_select_db(‘moviesite‘,$db) or die(mysql_error($db));$dir = ‘images‘;
$thumbdir = $dir.‘/thumbs‘;
?>
<html>
<head>
<title>Welcome to our Photo Gallery</title>
<style type="text/css">
th{ background-color:#999; }
.odd_row { background-color:#EEE;}
.even_row {background-color:#FFF;}
</style>
</head>
<body>
<p>Click on any image to see it full sized.</p>
<table style="width:100%">
<tr>
<th>Image</th>
<th>Caption</th>
<th>Uploaded By</th>
<th>Date uploaded</th>
</tr>
<?php
$result = mysql_query(‘select * from images‘) or die(mysql_error($db));
$odd = true;
while($row = mysql_fetch_assoc($result))
{
echo ($odd == true) ? ‘<tr class="odd_row">‘ : ‘<tr class="even_row">‘;
$odd = !$odd;
extract($row);
echo ‘<td><a href="‘ . $dir . ‘/‘ . $image_id.‘.jpg">‘;
echo ‘<img src="‘ . $thumbdir . ‘/‘ . $image_id . ‘.jpg" />‘;
echo ‘</a></td>‘;
echo ‘<td>‘.$image_caption.‘</td>‘;
echo ‘<td>‘.$image_username.‘</td>‘;
echo ‘<td>‘.$image_date.‘</td>‘;
echo ‘</tr>‘;
}?>
</table>
</body>
</html>
来看看最后显示缩略图的效果：
注意下面的代码：
$thumb_width = $width * 0.10;
$thumb_height = $height * 0.10;//创建一个缩略图
$thumb = imagecreatetruecolor($thumb_width, $thumb_height);
imagecopyresampled($thumb, $image, 0, 0, 0, 0, $thumb_width, $thumb_height, $width, $height);
//保存原图
imagejpeg($image, $dir . ‘/‘ . $_POST[‘id‘] . ‘.jpg‘, 100);
//保存缩略图
imagejpeg($thumb, $thumbdir . ‘/‘ . $_POST[‘id‘] . ‘.jpg‘, 100);
imagedestroy($thumb);
我们设置缩略图的长度是原来长度的10%，宽度也是原来宽度的10%，注意保持一致，否则图片会出现失真，当然这个参数如果设置成大于1的整数，图片就会放大。