Reviewing Web Graphic Formats


The HTML Web page format spurred the growth of the Internet not only because it could present information in an attractive graphic format, but also because its files were relatively compact in size for reasonable download times. In the spirit of preserving those download times, a few different new formats for graphics files also emerged. Through special compression technology, these file formats preserve color and detail while dramatically reducing file size ”sometimes eliminating megabytes in file size . Table 20-1 lists the most common Web graphic file formats and their features.

 
Table 20-1: Web Graphic File Formats

Format

Description


Compuserve GIF (.gif)

This mode requires conversion to Indexed Color mode (which limits the image to 256 colors) and enables you to preserve transparency so that the Web page background shows through.

JPEG (.jpe, .jpg, or .jpeg)

This mode does not preserve transparency, but it does enable you to specify the amount of compression to use so you can control file size and quality.

PNG (.png)

Portable Network Graphics (PNG) mode enables you to preserve transparency and choose specific methods for reducing colors and handling dithering in the image. This format isn't used often.

WBMP

This 1-bit color format optimizes images for wireless devices. Converting an image to this format converts it to simplified black and white.

Tip

Remember, when you create a new image with the File, New command, you click on the Transparent option button to set up an image with a transparent background. If you scan an image or download it from a digital camera, you cannot specify a transparent background, so it's best to copy a selection from such an image, create a new image with a transparent background, and then paste the copied selection into it.




Adobe Photoshop CS Fast & Easy
Adobe Photoshop CS Fast & Easy (Fast & Easy (Premier Press))
ISBN: 1592003451
EAN: 2147483647
Year: 2002
Pages: 179

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