Simply use a <thumb /> tag instead of <img /> when you wish to pull in
a thumbnail. Everything inside the <thumb /> tag (except for the src
parameter, which is modified to reference the generated thumbnail) will
be parsed directly to the resulting <img /> tag.

Example:

	<thumb src="pamela.png" />

will become

	<a href="/wp-files/thumbs/pamela.png">
	<img src="/wp-files/thumbs/pamela.png" />
	</a>

to the client.