Photoshop® CS4 Bible

24.2. Preparing Images for the Web

If you cast your memory back to the early days of the World Wide Web when 56K dial-up connections were the norm, you probably remember gnashing your teeth, waiting for what seemed like an eternity for Web pages to load. By necessity, Web designers had to optimize their images so that their pages would be fast and lean, or impatient viewers would be certain to turn away in disgust. With the ubiquity of broadband connection speeds, it's not as much of an issue now as it was even as recently as five years ago, but it's still a good practice to keep an eye on file sizes and compress your graphics properly. After all, many people are now connecting to Web sites via mobile devices, and you want your site's visitors to have a good experience no matter where they're coming from.

What follows is an examination of many of the most important things to consider when preparing images for use on the Web.

24.2.1. Web image file formats

As discussed back in Chapter 7, there are a few standard image formats that Web browsers can display: GIF, JPEG, PNG, and in rare cases, WBMP. Here's a quick review:

• GIF. Short for Graphic Interchange Format, GIF is one of the bread-and-butter image formats for displaying images on the Internet. Capable of displaying images with a maximum of 256 colors (or 8 bits per channel), this format is great at handling images with sharp distinctions between areas of solid color, such as line drawings, logos, or text.

  The colors that are ...