Hello Steven,
There are a lot of implementations of the Base64 algorithm, you can also use the following classes to convert your image files in order to embed them directly in you SVG content :
----- Original Message -----
From: Steven Dow
To: Batik Users
Sent: Tuesday, March 05, 2002 10:39 PM
Subject: Native Image format

Can someone tell me how a jpg is translated to the format below?  The documentation I've found does not give much detail about this method of embedding images.  If you paste this simple example into a new SVG file you will see the result is an image.  What is the translation algorithm?  Any help is much appreciated...