(Shelly Cashman Series) Gary B. Shelly, H. Albert Napier, Ollie N. Rivers-Web design_ introductory concepts and techniques -Cengage Learning (2008)

146 Chapter 5 Typography and Images
YOUR TURN
Exploring Web Image File Formats
1. Using the search tool of your choice and 2. Create a presentation for the class that
the keywords image file formats or similar describes the most commonly used image
keywords, search the Web for articles that file formats. Include a discussion of the
describe image file formats for the Web. pros and cons of each format and when,
as a Web designer, you would use each
format.
@SOURCE
Image Files
For more information
about working with
image files, especially
PNG images, visit the
Web Design Chapter 5
Online Companion page
(scsite.com/web3e/ch5/)
and then click Image Files
in the @Source links.
Web-ready Images
Creating Web-ready images involves using image editing software to refine and enhance
the images as necessary, selecting the right format for the type of image — for example,
selecting the GIF format for a diagram with less than 256 colors or the JPEG format for a
photograph with millions of colors — and then optimizing the images to find the balance
between the smallest possible image size and the highest possible quality.
Although more and more of your site’s visitors are likely connecting with high-speed
broadband, it is possible that some of your site’s visitors might still be using much slower
dial-up or high-speed dial-up connections. Images that are not optimized for size might
contribute to excessive Web page download times, leading to frustration on the part of
visitors still using slower connections. Additionally, images that are not optimized for size
are not an efficient use of server storage space. Finally, images that are not optimized for
quality will give your site an unprofessional appearance and will detract from your site’s
message. You can use image editing software to optimize your images by achieving a
balance between compressing your image files into a smaller size and maintaining the best
possible image quality.
Refining Your Images
You can use image editing software to refine your images to improve their quality.
For example, if an image contains more subject matter than you want to include, you can
use image editing software to crop the image. When you crop an image, you select the
part of the image you want to keep and remove the unwanted portion. Another benefit of
cropping an image is reduced file size. Figure 5-16 illustrates cropping an image in Adobe
Photoshop CS3.