About optimization
When preparing images for the
web and other online media, you often need to compromise between
image display quality and the file size of the image.
Save for Web & Devices
You can use
the optimization features in the Save For Web &
Devices dialog box to preview optimized images in different file
formats and with different file attributes. You can view multiple
versions of an image simultaneously and modify optimization settings
as you preview the image to select the best combination of settings
for your needs. You can also specify transparency and matting, select options
to control dithering, and resize the image to specified pixel dimensions or
a specified percentage of the original size.
When
you save an optimized file using the Save For Web &
Devices command, you can choose to generate an HTML file for the
image. This file contains all the necessary information to display
your image in a web browser.
Photoshop Save As and Image Processor
In
Photoshop, you can use the Save As command
to save an image as a GIF, JPEG, or PNG file. Depending on the file
format, you can specify image quality, background transparency or
matting, color display, and downloading method. However, any web
features—such as slices, links, and animations—that you’ve added
to a file are not preserved.
You can also use the Photoshop Image
Processor to save copies of a folder of images in JPEG
format. You can use the Image Processor to
resize and convert the images’ color profile to web standard sRGB.
Save For Web & Devices overview
You
use the Save For Web & Devices dialog
box (File > Save For Web &
Devices) to select optimization options and preview optimized artwork.
Save For Web & Devices dialog box
(Photoshop version)
- A.
- Display options
- B.
- Toolbox
- C.
- Optimize
pop‑up menu
- D.
- Color Table pop‑up
menu
- E.
- Animation controls (Photoshop
only)
- F.
- Zoom text box
- G.
- Preview
In Browser menu
- H.
- Original image
- I.
- Optimized
image
Preview images in the dialog box
Click a tab at the top of the image
area to select a display option: - Original
- Displays the image with no optimization.
- Optimized
- Displays image with the current optimization settings
applied.
- 2-Up
- Displays two versions of the image side by side.
- 4-Up
- Displays four versions of the image side by side.
Navigate in the dialog box
If the entire artwork is not visible in the
Save For Web & Devices dialog box, you can
use the Hand tool to bring another area into view. Use the Zoom
tool to magnify or reduce the view.
View optimized image information and download time
The annotation
area below each image in the Save For Web &
Devices dialog box provides optimization information. The annotation
for the original image shows the file name and file size. The annotation
for the optimized image shows the current optimization options,
the size of the optimized file, and the estimated download time
using the selected modem speed. You can choose a modem speed in
the Preview pop‑up menu.
Preview image gamma at different values
The
gamma value of a computer monitor affects how light or dark an image
looks in a web browser. In Photoshop, you can preview how your images
will look on systems with different gamma values and make gamma
adjustments to the image to compensate. Activating a preview option
does not affect final image output.
Choose one of the following options by using the
Save for Web/ & Devices dialog box Preview pop‑up menu - Monitor Color
- Makes no adjustments to image gamma. Monitor Color is
the default setting.
- Legacy Macintosh (No Color
Management)
- Simulates the default gamma of 1.8 used by Mac OS 10.5
and earlier.
- Windows (No Color Management)
- Simulates the default gamma of 2.2 used by Windows and
Mac OS 10.6 and later.
- Use Document Profile
- Adjusts the gamma to match any attached document color
profile in a color-managed document.
Optimize an image for the web
- Choose File > Save For
Web & Devices.
- Click a tab at the top of the dialog box to select a
display option: Optimized, 2‑Up, or 4‑Up. If you select 4‑Up, click
the preview you want to optimize.
- (Optional) If your image contains multiple slices, select
one or more slices you want to optimize.
- Select a preset optimization setting from the Preset
menu, or set individual optimization options. The available options
change depending on the file format you select.

If you’re working in 4‑Up mode, choose
Repopulate Views from the Optimize menu to automatically generate
lower-quality versions of the image after you change the optimization
settings.
- Fine-tune the optimization settings until you are satisfied
with the balance of image quality and file size. If your image contains
multiple slices, be sure to optimize all the slices.

To restore an optimized preview to the
original version, select it and then choose Original from the Preset
menu.
- If optimizing an image with an embedded color profile
other than sRGB, you should convert the image’s colors to sRGB before
you save the image for use on the web. This insures that the colors
you see in the optimized image will look the same in different web
browsers. The Convert to sRGB option is selected by default.
- (Photoshop
only) From the Metadata menu, choose what metadata to save with
the optimized file. (Choose File > File Info to
view or enter document metadata.) Metadata is fully supported by
JPEG file format, and partially supported by GIF and PNG file formats.
Note: The output metadata conforms to
Metadata
Working Group standards, so some JPEG metadata is stored
in the EXIF and IIM formats, rather than XMP.
- None
- No metadata saved (except for the EXIF copyright notice
in JPEG files). Produces the smallest file size.
- Copyright
- Saves copyright notice, rights usage terms, copyright
status, and copyright info URL.
- Copyright and Contact Info
- Saves all copyright information, plus the following information:
creator, creator job title, e-mail(s), address, city, state/province, postal
code, country, telephone(s), and website(s).
- All Except Camera Info
- Saves all metadata, except EXIF data about camera settings
such as shutter speed, date and time, focal length, exposure compensation,
metering pattern, and flash use.
- All
- Saves all metadata in the file.
- Click Save.
- In the Save Optimized As dialog
box, do the following, and then click Save:
Enter a file name, and select a location
for the resulting file or files.
Select a Format option to specify what kind of files
you want to save: an HTML file and image files, only image files,
or only an HTML file.
(Optional) Set output settings for HTML and image
files.
If your image contains multiple slices, select an
option for saving slices from the Slices menu: All Slices or Selected
Slices.

To reset optimization settings to the last
saved version, press Alt (Windows) or Option (Mac OS),
and click Reset. To keep the same settings the next time you open the
Save
For Web & Devices dialog box, press
Alt/Option and click Remember.
For a video on saving files for the web in Illustrator,
see www.adobe.com/go/vid0063.
Save or delete optimization presets
You can save optimization settings as a
named set and apply the settings to other images. Settings that
you save appear in the Preset pop‑up menu, together with the predefined
named settings. If you edit a named set or a predefined set, the Preset
menu displays the term “Unnamed.”
- Set optimization options as desired, and chooseSave
Settings from the Optimize palette menu.
- Name the settings, and save them in the appropriate folder:
- Photoshop
- (Windows XP) Document and Settings\[Username]\Application Data\Adobe\AdobePhotoshop
CS5\Optimized Settings
(Windows Vista) Users\[Username]\AppData\Roaming\Adobe\Adobe Photoshop
CS5\Optimized Settings
(Mac OS) Users/[Username]/Library/Preferences/AdobePhotoshop
CS5 Settings/Optimized Settings
- Illustrator
- (Windows XP) Document and Settings\[Username]\Application Data\Adobe\AdobeIllustrator
CS5 Settings\[Language]\Save for Web Settings\Optimize
(Windows
Vista) Users\[Username]\AppData\Roaming\Adobe\AdobeIllustrator CS5
Settings\[Language]\Save for Web
Settings\Optimize
(Mac OS) Users/[Username]/Library/ApplicationSupport/Adobe/Adobe
Illustrator CS5/[Language]/Save for Web Settings/Optimize
Note: If you save the settings in a another location,
they will not be available from the Preset pop‑up menu.
- To delete a preset, select the preset from Preset menu,
and select Delete Settings from the Optimize menu.
Work with slices in the Save For Web & Devices dialog box
If your image contains multiple slices,
you must specify the slices to be optimized. You can apply optimization
settings to additional slices by linking the slices. Linked slices
in GIF and PNG‑8 format share a color palette and dither pattern
to prevent the appearance of seams between the slices.
Compress a web graphic to a specific file size
- Choose File >
Save For Web & Devices.
- Click a tab at the top of the Save For Web &
Devices dialog box to select a display option: Optimized, 2‑Up,
or 4‑Up. If you select 4‑Up, select the preview you want to optimize.
- (Optional) Select the slices you want to optimize and
the file format you want to use.
- Select Optimize To File Size from the Optimize menu (to
the right of the Preset menu).
- Enter the desired file size.
- Select a Start With option:
- Current Settings
- Uses the current file format.
- Auto Select GIF/JPEG
- Automatically selects the optimal format depending on image
content.
- Select a Use option to specify whether you want to apply
the specified file size to current slice only, to each slice in
the image, or to all slices. Click OK.
Resize artwork while optimizing
In the Save For
Web& Devices dialog box, you can resize an image
to specified pixel dimensions or to a percentage of the original
size.
- Click the Image Size tab
in the Save For Web & Devices dialog
box.
- Set any of the additional options:
- Constrain Proportions
- Maintains the current proportions of pixel width
to pixel height.
- Quality
- (Photoshop only) Specifies the interpolation method.
Bicubic Sharper generally produces better results when you are reducing
image size.
- Anti-Alias
- (Illustrator only) Removes jagged edges
in the artwork by applying anti-aliasing.
- Clip To Artboard
- (Illustrator only) Clips the artwork size to match the document’s
Artboard boundary. Any artwork outside the Artboard boundary will be
deleted.
Note: None of the features in the Image
Size palette are available for the SWF and SVG file
formats except Clip To Artboard.
- Enter new pixel dimensions or specify a percentage by
which to resize the image, and click Apply.
Generate CSS layers for web graphics
You can use layers in your Illustrator
artwork to generate CSS layers in the resulting HTML file. A CSS
layer is an element that has an absolute position and can overlap
with other elements in a web page. Exporting CSS layers is useful when
you plan to create dynamic effects in your web page.
The Layers
palette in the Save For Web & Devices
dialog box gives you control over which top-level layers in your
artwork are exported as CSS layers, and whether exported layers
are visible or hidden.
- Click the Layers tab in the Save For
Web & Devices dialog box.
- Select Export As CSS Layers.
- Select a layer from the Layer pop‑up menu, and set the
following options as desired:
- Visible
- Creates a visible CSS layer in the resulting HTML file.
- Hidden
- Creates a hidden CSS layer in the resulting HTML file.

CSS
layers are the same as GoLive layers. Using Adobe GoLive, you can
animate a CSS layer and use built‑in JavaScript actions to create
interactive effects.
Preview optimized images in a web browser
You
can preview an optimized image in any web browser installed on your system
from the Save For Web & Devices dialog
box (File > Save For Web & Devices).
The browser preview displays the image with a caption listing the image’s
file type, pixel dimensions, file size, compression specifications,
and other HTML information.
- To preview an image in your default
web browser, click the browser icon at the bottom of the Save For
Web & Devices dialog box.
- To select a different browser, select Other from the
browser pop‑up menu (next to the browser icon).
- To add, edit, or remove a browser in the browser pop‑up
menu, select Edit List from the browser pop‑up menu. In the Browsers
dialog box, you can find all browsers on your computer and set the
default browser to preview your image.
Save a file to e‑mail
- Choose
File > Save For Web & Devices.
- Click the Optimized tab at the top of the Save For
Web& Devices dialog box.
- Choose JPEG Low from the Preset menu.
- In the Image Size area, click
the chainlink icon to the right of the W and H boxes to retain image
proportions. Then enter a width.
For e‑mail, 400 pixels is a good size. Use a smaller size
if your recipient has a slow Internet connection.
- Click Save. Enter a file name and location in which to
save the file. Under Format, make sure that Images Only is selected.
Again click Save.
Now you are ready to e‑mail the file. In some e‑mail programs,
you can drag the file into the body of the message. In other programs,
you use the Attach or Insert command.
More Help topics
Save for web in Illustrator video