Chapter 1, Rule 1: Make Fewer HTTP Requests
1- Image Maps:
There are drawbacks to using image maps.Defining the area coordinates of the image map, if done manually, is tedious and error-prone
2- CSS Sprites:
CSS sprites combine multiple images into a single image, an example of such an image:
To use an image from the sprite:
3- Inline Images:
<IMG ALT="Red Star"
URL scheme is not supported in Internet Explorer (up to and including version 7), there is a limitation on the size, sure it is not cached.
4- Combined Scripts and Stylesheets
Rather than having multiple CSS files, combine them in one file, same thing for Scripts files. Sure the idea is against writing a modular code, combine these files in the build process.