Applying optimization settings

To optimize a file for the Web, you import a Smart Photoshop object and choose a format and options for the format in the Save For Web dialog box. You can also optimize an image to match a specified file size. This feature enables you to quickly achieve a desired file size without having to test different optimization settings.

To optimize an image as a JPEG:

1 Choose a JPEG setting from the Settings menu of file formats in the Save For Web dialog box.

2 Choose an option for specifying image quality:

A higher quality setting preserves more color information but results in larger file sizes. View the JPEG at several quality settings to determine the best balance of quality and file size.

3 To create an enhanced JPEG with a slightly smaller file size, select the Optimized option.

Note: The Optimized JPEG format is recommended for maximum file compression. However, some older browsers do not support this feature.

4 Select the Progressive option to create an image that displays progressively in a Web browser. The image will display as a series of overlays, enabling viewers to see a low-resolution version of the image before it downloads completely. The Progressive option requires use of the Optimized JPEG format. Selecting Progressive automatically selects Optimized.

Progressive JPEGs require more RAM for viewing, and are not supported by some browsers.

5 To apply a blur to the image to smooth rough edges, enter a value for Blur or drag the pop-up slider.

This option blurs pattern artifacts created along sharp edges in the image and creates a smaller file size, but may also reduce image detail. A setting of 0.1 to 0.5 is recommended.

The Blur option applies an effect identical to that of the Gaussian Blur filter in Photoshop.

6 To preserve the ICC profile of the image with the file, select ICC Profile.

Note: ICC profiles are used by some browsers for color correction. The ICC profile option preserves ICC profiles embedded by Photoshop.

7 If the original image contains transparency, select a Matte color to simulate the appearance of background transparency. See Making transparent and matted Photoshop images.

8 Click OK and save the file with the .jpg extension.

To optimize an image as a GIF or PNG-8:

1 Open the original file, and then choose any GIF or PNG-8 format from the Settings menu of file formats in the Save For Web dialog box.

2 For GIF format only: Drag the Lossy slider or enter a value to allow the compression process to remove pixels from the image (and reduce file size).

You can often apply a Lossy value of 5%-10%, and sometimes up to 50%, without degrading the image. File size can often be reduced 5%-40% using the Lossy option. See Previewing and controlling application dither.

Note: You cannot use the Lossy option with the Interlaced option, or with Noise or Pattern Dither algorithms.

3 Select a color palette, as described in Selecting a color table option.

4 To choose a specific number of colors, select a number from the Colors pop-up menu, enter a value in the number field, or use the arrows to change the number of colors.

This option specifies the maximum number of colors. If the image contains fewer colors than the number specified, the color palette will contain only the number of colors in the image.

5 Select Interlaced to create an image that displays as low-resolution versions in a browser while the full image file is downloading. Interlacing can make downloading time seem shorter and assures viewers that downloading is in progress. However, interlacing also increases file size.

6 Select a Dither option and amount. For information on dither, see Previewing and controlling dithering in Photoshop images.

7 If the image contains transparency, choose an option for preserving or filling transparent pixels:

Note: The original image must contain transparent pixels in order for you to create transparency in the optimized image. You can use the magic eraser tool () to easily create transparency in a document. In Photoshop, you can also use the background eraser tool ().

For more information on setting transparency and Matte color, see Making transparent and matted Photoshop images.

8 To automatically shift colors to the closest Web palette equivalents (and prevent the colors from dithering in a browser), drag the Web Snap slider or enter a value to specify a tolerance level for colors to be shifted. A higher value shifts more colors. See Previewing and controlling dithering in Photoshop images.

9 Click OK and save the file with the .gif or .png extension.

To optimize an image as a PNG-24:

1 Open the original file, and then choose PNG-24 from the Settings menu of file formats in the Save For Web dialog box.

2 Select Interlaced to create an image that displays low-resolution versions in a browser while the full image file is downloading. Interlacing can make downloading time seem shorter, and assures viewers that downloading is in progress.

3 If the image already contains transparency, choose an option for preserving or filling transparent pixels:

4 Click OK and save the file with the .png extension.

To optimize a file according to a specified file size:

1 In the Optimize panel of the Save For Web dialog box, select Optimize to File Size from the Optimize panel menu.

2 Specify a Start With option:

3 Enter a value for file size.

4 Click OK.

Images and Page Design > Choosing options in the Save For Web dialog box > Applying optimization settings