imagejpeg()

(PHP 4, PHP 5, PHP 7)

输出图象到浏览器或文件。

说明

imagejpeg()从$image图像以$filename为文件名创建一个JPEG图像。

参数

由图象创建函数(例如imagecreatetruecolor())返回的图象资源。

文件保存的路径，如果未设置或为NULL，将会直接输出原始图象流。

如果要省略这个参数而提供$quality参数，使用NULL。

$quality为可选项，范围从 0（最差质量，文件更小）到 100（最佳质量，文件最大）。默认为 IJG 默认的质量值（大约 75）。

返回值

成功时返回TRUE，或者在失败时返回FALSE。

范例

输出 JPEG 图像

以上例程的输出类似于：

保存一副 JPEG 图像

以 75%的图像质量输出图像

注释

Note:

如果想输出渐进式 JPEG，需要用imageinterlace()函数将隔行扫描比特置位。

参见

• imagepng()以 PNG 格式将图像输出到浏览器或文件
• imagegif()输出图象到浏览器或文件。
• imagewbmp()以 WBMP 格式将图像输出到浏览器或文件
• imageinterlace()激活或禁止隔行扫描
• imagetypes()返回当前 PHP 版本所支持的图像类型

I didn't find any example like this on the Web, so I mixed pieces together.. hope this will save time to other people!
Here's a complete solution to READ any image (gif jpg png) from the FILESYSTEM, SCALE it to a max width/height, SAVE the scaled image to a BLOB field keeping the original image type. Quite tricky.. 

So, let's suppose you have a form where a user can upload an image, and you have to scale it and save it into your database. 

If string $filename is given and it exists, it will be overwritten.

[[Editor's note: removed the header() call since it is not required when outputting inline image-data]]
One single code line, solve-me after 3 hours of blind search!
here is:
... ob_start();
 imagejpeg( $img, NULL, 100 );
 imagedestroy( $img );
 $i = ob_get_clean();
echo ""; //saviour line!

Regarding Carl Gieringer's comment, it is possible to have PHP files in utf-8. Just make sure the editor does not output BOM, which is unnecessary in utf-8 anyway.
Except for any editors from Microsoft, most programmer's editors that supports utf allows you to surpress BOM.

Here is the simple, but powerful script for creating thumbnails on the fly. 
You can include the script 
directly to www page - just put it in "Content-type: image/jpeg");
  $im   = imagecreatefromjpeg($pic);
  $orange = imagecolorallocate($im, 220, 210, 60);
  $px   = (imagesx($im) - 7.5 * strlen($string)) / 2;
  $old_x=imageSX($im);
  $old_y=imageSY($im);
  $new_w=(int)($width);
  if (($new_w$old_x)) {
   $new_w=$old_x;
  }
  $new_h=($old_x*($new_w/$old_x));
  if ($old_x > $old_y) {
    $thumb_w=$new_w;
    $thumb_h=$old_y*($new_h/$old_x);
  }
  if ($old_x 

For those looking to grab the resolution of a JPEG image without using GD nor ImageMagic... I wrote this simple function.
Too bad GD doesn't have this very simple function for us to use... 

I worked out a script that allows the transfer of alphanumeric data to be placed on an image. The HTML feature is img src and the php feature is imagettftext. This simple code will increment from 1 to 3 on images.
code:

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