Exporting JPEG Images

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The GIF option exports 8-bit images, or a maximum of 256 colors, and works well for line art and images with solid colors. For photographs or any artwork with gradations or millions of colors, you'll want to export in JPEG format. JPEG is a lossy compression scheme, meaning that it looks at your image and removes information as part of its compression algorithm.

On the home page you are creating, you have some buttons, text, the logo, and the images used for the disjointed rollovers. The GIF controls you set in the last exercise will work for all areas of the page except for the images in the disjointed rollovers. For these images, you want to use JPEG compression. You already have a slice over the exact area that you used to create the rollovers. You can simply select the slice and change the optimization settings for just that slice.

1.

Select the slice over the picture of the girl. Select JPEG - Better Quality from the Saved Settings pop-up menu on the Optimize panel. Click the 4-Up button to preview the image. Use the Hand tool to move the girl into view.

By increasing the compression level in a JPEG image, you reduce the quality. In this image, the quality is set to 80 percent.

2.

Select the image in the top-right preview and then drag the Quality slider on the Optimize panel to 60 percent.

Look at the image compared to those in the other preview windows. It appears softer, but still is an acceptable image. The file size is a little smaller.

3.

Select the image in the bottom-right preview and drag the Quality slider on the Optimize panel to 35 percent.

At this setting, the image displays compression artifacts areas where you can see blocks of pixels. The file size savings does not justify the quality loss.

4.

Select the image in the bottom-left preview. Change the Export format to JPEG, move the Quality slider to 50 percent, and change smoothing to 1 in the Smoothing pop-up menu.

The compression scheme in JPEG format sometimes leaves rough or blocky areas on the image. Smoothing is a method of blurring those rough edges so they are not as noticeable. The file size is reduced slightly with smoothing.

After you choose your export file format settings, you can save them for future export operations or for batch processing. All of the settings on the Optimize panel are saved.

5.

Select the top-right preview.

You want to save the optimization settings used on this preview. These settings are used when you export or save the settings or save the file.

6.

Chose Save Settings from the Optimize panel Options menu. Type a name for your settings in the Preset Name text box. Click OK.

The name of the saved settings now appears in the Settings pop-up list on the Optimize panel. This collection of settings remains for your use until you delete it. To use these settings in other images, choose the name of the settings from the Settings pop-up menu on the Optimize panel.

7.

Click the Original button to return to the document window and save your file.

Your settings are available for you to use on all your images where you want the same optimize options. To use your saved settings, choose the name from the Settings pop-up menu on the Optimize panel.

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    Macromedia Fireworks 8(c) Training from the Source
    Macromedia Fireworks 8: Training from the Source
    ISBN: 0321335910
    EAN: 2147483647
    Year: 2005
    Pages: 239
    Authors: Patti Schulze

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