With jpeg files, you can specify amount of file compression but some of the information is lost during compression. They can use up to 256 colors and are best for images with areas of a single color. GIF files may be compressed without loss of information. Other files and anchors are the targets of links. A link can be either an absolute link or a relative link.
Absolute links specify the full location of a file.
You can only use absolute links to link to a file on a different server or disk. Relative links omit part of the file specification and use the current location as the default. It's usually best to use relative links within your own web site. Relative links allow you to move the entire directory tree to a new location without breaking your links. You should try to use absolute links only to references files outside your own web.