Adobe Photoshop CS2 On Demand [Electronic resources]

Optimizing a GIF Document

The GIF file format is used primarily for images that contain solid colors with sharp edges, such as clipart, text, line art, and logos. Since the Internet is a slow device, using the GIF format on images significantly reduces their file size, and will create fast-loading graphics. The GIF format utilizes an 8-bit pixel, and creates a document with a maximum of 256 colors (the less colors the smaller the file size). The GIF format has been around long enough for it to be considered an Internet "native" format. A

native format is one that does not require a specific plug-in for the browser to display the file.

Optimize a GIF Document

Open a document in ImageReady by first opening the image in Photoshop and then click the

Jump To ImageReady button.

Click the

Original, Optimized, 2-Up , or

4-Up palettes to view the document using different layouts.

Click one of the sample images to change its default format.

Select the

Optimize palette.

Click the

Format list arrow, and then click

GIF .

Click the

Color Table arrow, and then select from the following options:

• Reduction. Click to select a visual reduction method for the image colors.

• Colors. Enter or select a value from 2 to 256 maximum colors.

• Web Snap. Enter or select a value from 0 to 100 to instruct the GIF compression utility how many of the image colors should be Web safe.

Click the

Dither arrow, and then select from the following options:

• Method. Click the list arrow, and then select from the available dithering schemes. Dithering is how the GIF format mixes the available image colors.

• Amount. Enter or select a value from 0 to 100 to instruct the GIF compression utility how many of the image colors should dither.

Click the

Transparency arrow, and then select from the following options:

• Transparency. Check to make the transparent areas of a GIF image transparent.

• Matte. Click to fill the trans-parent areas of a GIF image.

• Dither. Click to select a dithering scheme, and enter an amount for the mixing of the matte color.

Click the

Options arrow, and then select from the following options:

• Interlaced. Check to have the GIF image load in three scans.

• Lossy. Enter or select a value from 0 to 100 to instruct the GIF compression utility how much image loss is allowed.

• Use Unified Color Table. Check to have the GIF format apply a universal color table to all images used in a rollover image.

• Add Metadata. Check to embed recoverable data about the files colors, creation, and even author information.

Click the

File menu, and then click

Save Optimized .

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