PS中的 另存为 与 另存为网页格式上

周多前在网上搜到的一篇技术文档，觉得还不错。虽然平时用ps时大概也能知道哪种保存方式更合适，但基本停留在经验基础上，而这篇文章对另存为和另存为网页格式有详细的文件数据分析，觉得比较有做参考资料的价值，所以决定翻译一下。

翻译之前觉得很短一篇，不过真正翻时感觉长了五倍都不止，一看全篇英文就犯困，翻翻停停拖了很久才算差不多了。我用英文版ps，很多术语不清楚中文怎么说，外加英语烂，所以可能翻译有些问题，望大家指正。--tea00

原作者 www.impulseadventure.com

Photoshop Save As vs Save For Web

One of the more confusing options in Photoshop CS2 arises when it comes time to save your edited image. There are two methods to save your photo: using the Save As dialog box or using the Save For Web dialog box. This article answers the question: what are the differences between save for web and save as, and when should I use Save for Web?
Photoshop offers two options to save your image after editing:

File -> Save As ...
File -> Save For Web ...
Both of these menu otpions create an output JPEG file from your working image, but they differ in both the available options, flexibility and representation of JPEG compression quality.

Photoshop另存为和另存为网页格式

Photoshop cs2中最易混淆的选项之一是在保存编辑过的图片时，有两种保存图片的方式——另存和另存为网页格式。本篇文章将解答另存和另存为网页格式有何区别，以及何时应该选择保存为web格式。

Photoshop提供了两种保存编辑过的图片的方式

文件->另存为
文件->另存为网页格式
两种保存方式都可以输出jpeg格式图片，但两种方式在jpeg压缩质量的选项、灵活度和表现上有所区别。

Quick Choice

If you plan to...【You should use】
Create images for your website, or optimize the file as small as possible【Save For Web 】
Share images with others, and you want viewers knowing shot time/date, etc. 【Save As 】
Share images with others, and you do not want others knowing shot time/date, etc. For example, stock photos, or concerns over privacy 【Save For Web】
Convert your image to a given file size, or you want interactive feedback on quality settings 【Save For Web】
... for all other cases【Save As】

快速选择

如果你想要…【那么选择的保存方式是】
创建网页使用的图像，或者想尽可能的优化图像文件的体积【另存为网页格式】
和他人分享图片，而且你希望别人知道你拍摄照片的时间日期等【另存为】
和他人分享图片，但你不希望别人知道你拍摄照片的时间日期等，比如用于图片库，或是需要保护隐私【另存为网页格式】
把图像文件压缩到指定的大小，或者你想要在设定图像质量时能有交互的反馈【另存为网页格式】
其它情况【另存为】

Photoshop Save As

The Save As dialog includes a very large number of output file formats, as it is the standard method by which users will generate their final image files. As this output method is not optimized towards transmission over a low data-rate medium (such as the internet), additional information is encoded into the resulting image at the cost of increased file size. As shown below, this additional data may consume approximately 40KB.
One of the main reason that photographers choose Save As instead of Save for Web when sharing photos is so that the EXIF metadata (which includes camera information and shot details) can be displayed to other interested viewers. Most photo sharing sites (such as pbase) automatically extract this EXIF information, for the benefit of other photographers. However, considering that it also includes the time and date of the original shot, it may have privacy implications.

Photoshop 另存为

另存为是用户输出最终图像文件的标准方式，因此对话框中有输出多种文件格式的选择。这种保存方式没有为低速数据传输方式（例如互联网）优化文件，保存的图像文件中包含了附加信息，因此文件体积较大。如后面所示，这些附加数据的体积可能接近40kb。

摄影者通常选择另存为而不是另存为网页格式的一个主要的原因是，在分享照片时，观看者能够查看到图片的Exif信息（包括相机和拍摄信息）。大部分照片分享网站（例如pbase）都能自动提取Exif信息，以方便其它摄影者查看。尽管如此，Exif信息包含着照片拍摄的时间日期信息，所以可能涉及隐私。

16-bit Mode
As Save As does not support for 16-bit images, it may be necessary to convert to 8-bit first, save and then undo the color depth conversion step if you plan to continue working on the file. You can convert to 8 bit RGB by selecting Image -> Mode -> 8-bits/channel. Save for Web automatically converts the color depth for you.
16位模式
由于”另存为”不支持保存16位模式的图像，所以有必要先转换成8位模式，保存。如果你要继续处理图片的话，就撤销上一步颜色位深的设置。把图像转为8位RGB图像的方式是菜单上的图像->模式->8位/通道。另存为网页格式会自动为你转换颜色位深

Photoshop Save For Web

The Save For Web dialog box doesn't provide as much flexibility in the ouput image file formats as the Save As dialog, but it does offer more flexibility with each supported option. Supported output file formats include:

JPEG - Selection of Quality level (1-100). No transparency.
GIF - Different palette sizes (2-256) and dithering options define quality. Supports single-bit transparency.
PNG-8 - Reduced color depth (2-256 colors) and dithering options defines quality. Supports multi-bit transparency.
PNG-24 - "Lossless" 24-bit quality. Supports multi-bit transparency.
WBMP - Black & White dithered output.
（附图见下面的中文版）
Main window for Save for Web
The focus on this page will be on the JPEG output format.

Photoshop另存为网页格式

另存为网页格式没有像另存为那样提供很多中保存图像文件的格式选择，但是它为每种支持的格式提供了更灵活的设置。支持的格式包括：

Jpeg－可以设置图像保存质量（1－100％）。无透明度。
Gif－通过设置调色盘大小（2－256色）和颜色抖动来确定保存图片的质量。支持单色透明度。
Png-8－通过设置调色盘大小（2－256色）和颜色抖动来确定保存图片的质量。支持单色透明度。（原文中png-8透明度的说法貌似有误？）
Png－24－无损24位质量。支持透明度。

另存为网页格式的主窗口
按上图中的设置将输出jpeg格式文件。

Save For Web JPEG output

Because the Save for Web command is intended to be used for images that are destined for display on the internet, one of the primary goals is in optimizing the file size as much as possible while still retaining acceptable image quality. To this end, two methods are used to achieve this: a) a live preview of changing JPEG compression quality sliders and b) the removal of all unnecessary metadata (JPEG markers) in the output file.

The main features in Save for Web include:

Optimize to File Size: Ability to automatically select both the file format (JPEG or GIF) and JPEG compression level to achieve the selected file size.
Removal of EXIF metadata. For many this is a useful feature, while others will completely avoid Save for Web because of it. For simple images on a web site or for privacy reasons, you may want to hide the time/date a photo was taken, or other parameters. But, if you plan to share your images on a photo hosting site and would like to indicate the focal length, aperture and other parameters to your viewers, Save for Web will not be the right method.
Removal of Optional Markers. In most output JPEG files, special markers are used to indicate additional information or provide resiliency in the case of errors / corruption. The Save for Web method will remove these and still allow JPEG decoders to work.
另存为网页格式之jpeg输出

保存为网页格式目的是输出展示在网页上的图片，保存的主要的目的之一是在维持图片质量的同时尽可能地缩小文件体积。保存为网页格式使用了两种方法达到此目的：a) 在拖动滑动条更改jpeg质量设置时提供即时预览；b）移除输出文件中所有不必要的信息（jpeg标记）。

另存为网页格式的主要特色有：

优化文件大小：可以自动选择文件格式（jpeg或gif）和选择jpeg的压缩率，以实现选定的文件大小。
移除Exif信息。很多时候这是一个有用的功能，而另一些人则会因为此功能而不使用另存为网页格式。对于简单的网页图片来说，或者出于保护隐私，你也许希望隐藏照片拍摄的时间日期以及其它参数。但是，如果你想要在网络相册中分享你的照片，并且希望观看者看到拍摄的焦距、光圈和其它参数，那么就不适合使用另存为网页格式了。
移除可选的标记。在大多数jpeg文件中，有一些记录附加信息、或是在出错/崩溃时用以恢复的特殊标记。另存为网页格式会在jpeg文件依然能被解码的前提下移除这些标记