Easy Animation Using the Horizontal Transform Feature
Copy and paste the image below in Fireworks:

Open the Frames Panel (Window>Panel>Frames). Duplicate the Frame by dropping down the menu and selecting duplicate frame.

You now have two frames containing the same picture. Click on Frame 2 then click on the Layers tab to return to the layers panel:

At the layer panel click on the layer that contains the picture, it will turn blue as shown below:

Now you need click Modify on the Menu toolbar>>Transform>>Flip Horizontal. This makes a mirror image of the juggler in frame two as shown below:
Now we need to set the frame rate so that it moves shower than the default 7 rates per second. Return to the Frames Panel by clicking on the Frame tab. Select both Frame 1 and Frame 2 by holding down the shift key and clicking on Frame 1 and Frame 2. Both should be selected as shown below:

Then double click on the highlighted frames to open the frame rate dialog box and type in a new frame rate as shown below:

To view the animation, click on the preview tab in the main document window then click the white arrow to play the animation.

If the animation is to your liking, you will need to export it as an animated gif!! If you just export it, you will only export one frame, not two. Click on File>>Export Preview and select animated gif from the dropdown menu. Click next and give it a name.

This is how my animated juggler turned out:

How easy was that!!!