Working with GIF files

Corel PaintShop Pro lets you optimize GIF files to maximize quality while minimizing file size. You can save images with or without transparency, depending on how you want to display them on your Web pages.

Paletted images (those with 256 or fewer colors, such as GIF or PNG files) do not support transparent backgrounds, but you often need to make part of your image transparent for a Web page. For example, you may have a round logo and want to display the background of the Web page around the logo. In this case, you can choose not to display one color. Most Web browsers support this option, effectively making that color transparent.

The GIF Optimizer dialog box contains four tabbed areas in which to configure the transparency, color, and format options of the file. The fifth tabbed area displays estimated download times of the image at various modem speeds.

GIF Optimizer Transparency

You can choose to base transparency on existing image or layer transparency, or you can sample a color in the image that you want to make transparent. If you have a selection in your image, you can base the transparency on the selection.

GIF Optimizer Partial Transparency

A GIF file cannot contain partially transparent pixels. All pixels must be either transparent or opaque (visible). Original images may contain partially transparent pixels if the image does not have a background layer, and you have reduced the opacity of a layer, added a mask, feathered a selection, or used a brush at a reduced opacity setting. You can determine whether the partially transparent pixels become transparent or opaque, and whether they are blended with another color.

Important! If you mark the None option under the Transparency tab, the options in this area are unavailable.

GIF Optimizer Colors

GIF images have an 8-bit color depth, which means they can display up to 256 colors. Because these colors are stored in a palette, an image containing 256 or fewer colors is called a paletted image. To reduce file size, you can have fewer than 256 colors. You can use the options under this tab to select the number of colors and the type of palette used.

GIF Optimizer Format

GIF images can be interlaced or non-interlaced, which affects how the image is displayed on a computer with a slow Internet connection. You can also save the image to an older version of the GIF format to enhance compatibility with older applications.

GIF Optimizer Download Times

The Download Times tabbed area in the GIF Optimizer dialog box displays the size of the compressed file and estimated download times for four different Internet speeds. If the file size is too large, you can decrease it by reducing the number of colors.

Using the Transparent GIF wizard

You can open the Transparent GIF wizard from the GIF Optimizer dialog box. This wizard guides you through the steps of optimizing a GIF file.

What is interlacing?

Interlacing is a method that lets you display a Web-based image on the screen at a low, blocky resolution. As the image data loads, the image quality improves.

To optimize and save a GIF file Back to Top

Edit workspace 

To use the Transparent GIF wizard Back to Top

Edit workspace 

 

On page 5 of the wizard, click Back to return to the previous pages, change the settings you want, and return to page 5 to view the results.

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A GIF image cannot contain partially transparent pixels. If the image contains them, the Transparent GIF wizard blends them with the color you choose. Reducing layer opacity, adding a mask, feathering a selection, and using a brush set at reduced opacity are some of the actions that can produce partially transparent pixels.

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You can click the Download Times tab to preview the file size of the compressed file and view an estimate of the download time at four modem speeds.


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