Adobe Photoshop CS3 - Manual (Page 532)

PHOTOSHOP CS3
User Guide
525
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 browser dither
If an image contains more colors than the monitor can display, the browser will dither, or approximate, the colors
that it cannot display by blending colors that it can.
❖ To show or hide the preview of browser dither, choose Browser Dither from the Preview pop-up menu. A check
mark indicates that browser dithering is active. Activating Browser Dither does not affect final image output.
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. Windows
systems use a gamma of 2.2, so images look darker on Windows than on Mac OS systems, which are normally set to
a gamma of 1.8. 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
Uncompensated Color Makes no adjustments to image gamma. Uncompensated Color is the default setting.
Standard Windows Color Displays an adjustment based on the default Windows gamma.
Standard Macintosh Color Displays an adjustment based on the default Macintosh gamma.
Use Document Color Profile Adjusts the gamma to match any attached document color profile in a color-managed
document.
Optimize an image for the web
1 Choose File > Save For Web & Devices.
2 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.
3 (Optional) If your image contains multiple slices, select one or more slices you want to optimize.
4 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.
5 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.
6 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. On the Optimize menu, make sure that Convert to sRGB is
selected.