Thanks for the reply, Lee.
The overall image is a montage of overlapping photos created in Photoshop. The client really likes it but the unsliced size is 432px wide by 1390px high. I sliced into two columns and six rows making each slice 216 x 231 for a more digestible download.
After I posted this last night, I experimented with using a table. I got what I was after but it will be a little clunky to explain.
In the container, I selected "Edit Text" and created a 2-column 6-row table at 50% width in the container. I left the border at "1" (so I could still see the table) and put cell padding and cell spacing at "0".
When placing an image slice in the left column, I chose right alignment and entered "0" for vspace and hspace. For an image slice in the right column, I chose left align and "0" for vspace and hspace.
Once I had placed all of the image slices, (and while still in the text editor) I switched from design to HTML. I changed the border from "1" to "0", clicked "Update" and it looked like it was supposed to without any annoying gaps or alignment problems.
That was late last night. I only previewed it in IE6. I will check in Firefox and Opera in a moment.
Since I'm still in the construction stage of this particular portal on my localhost, I'll give your suggestions a spin and let you know what happens.
Thanks again.