Limitations of png-8

Slices with png at 256 colors in the center of the above image shows banding, particularly in wall over blue vase.
png-8 slice is 37k.

Slices with jpeg in center, above, shows even tone throughout.
And the jpeg slice is 27k, a 10k savings.
By having slices on the outside that are png-8, and a slice on the inside that's a jpeg,
you maintain the transparency of the edges without losing the detail in the image,
at the expense of a little more complexity.
Fireworks exports images in a table or in css.