Needed to Uninstall Fireworks (advice)

I needed to uninstall Fireworks CS6 today - as it always came up when I clicked on any image that should have opened (Preview).

Is this needed at all? It came with my CS6 and not sure if I can re-install at any point in the future - as I can't locate the icon to re-install the thing.

But really have no idea why this started opening up today.

Any advice would be great: Daryl