Adobe 29180155 User Guide - Page 272

ADOBE PHOTOSHOP ELEMENTS 4.0 267 User Guide To preserve background transparency in a GIF or PNG image GIF and PNG-8 formats support one level of transparency-pixels can be fully transparent or fully opaque, but not partially transparent. (By contrast, PNG-24 format supports multilevel transparency; that is, you can have up to 256 degrees of transparency in an image, ranging from opaque to completely transparent.) 1 In the Editor, open or create an image that contains transparency, and choose File > Save For Web. 2 In the Save For Web dialog box, select GIF, PNG-8, or PNG-24 as the optimization format. 3 Select Transparency. 4 For GIF and PNG-8 format, specify how to treat partially transparent pixels in the original image. You can blend these pixels with a matte color, or you can create hard-edged transparency. See also "About GIF format" on page 260 "About PNG-8 format" on page 260 "About PNG-24" on page 261 To create a matted GIF or PNG image When you know the background color of the web page on which an image will be displayed, you can use the matting feature to fill or blend transparent pixels with a matte color that matches the web page background. 1 In the Editor, open or create an image that contains transparency, and choose File > Save For Web. 2 In the Save For Web dialog box, select GIF, PNG-8, or PNG-24 as the optimization format. 3 For GIF and PNG-8 format, do one of the following: • To keep fully transparent pixels transparent, and blend partially transparent pixels with the matte color, select Transparency. This option prevents the halo effect you see when you place an anti-aliased image on a web page background that differs from the image background. This option also prevents the jagged edges of hard-edged transparency. • To fill transparent pixels with the matte color and blend partially transparent pixels with the matte color, deselect Transparency. 4 Select a color from the Matte menu: Eyedropper Color (to use the color in the eyedropper sample box), White, Black, or Other (to select a color using the Color Picker). See also "About GIF format" on page 260 "About PNG-8 format" on page 260 "About PNG-24" on page 261 To create hard-edges transparency in a GIF or PNG-8 file Use hard-edged transparency when you don't know the background color of a web page, or when the web page background contains a texture or pattern. However, keep in mind that hard-edged transparency can cause jagged edges in the image. 1 In the Editor, open or create an image that contains transparency, and choose File > Save For Web.