It's actually very easy to include graphics in your document,
as long as you use the graphics package as discussed
above. This package makes available the
\includegraphics command, which takes the name
of a graphics file as a parameter. For example:
Graphics files can be in
EPS (Encapsulated PostScript) format, and other
formats such as GIF or JPEG might also work.
EPS is especially good for diagrams.
and drawing programs can export images as EPS.
If you want to center an image on the page, put
it into a center environment. Here, for
example, is the LATEX lion, scanned from Leslie Lamport's
original LATEX User's Guide and Reference Manual: