Click the Texture Transfer icon select Transfer Full and click Apply. Presto! Your first section is now done. Move it off to one side now and drag over another of your blank rectangles over the top right section of your original sprite. This time, in the Align section of the Arrange palette, you'll click the top right corner button to align those up.

Repeat this process for the bottom left and bottom right. That's it for the image part of this. Now all you have to do is create the tables in your HTML to reconstruct the images. Remember to use border="0" cellpadding="0" cellspacing="0" in your tables and set the table width to the exact pixel width as your finished image.