Export Responsive Prototype is an extension for Adobe Fireworks that allows you to simulate responsive design when you put designs for each media query breakpoint on separate pages.
To indicate which sections of the design “respond” you simply slice the document, making sure that clear rows are defined. For areas that don’t have slices, or just plain slices, their widths will be converted to percentages. By adding either ‘fixed’, ‘left’, ‘center’ or ‘right’ in the slice’s target field, you can force slices to be not to scale. ‘left, ‘center’ and ‘right’ will absolutely position the slices to the respective anchor point of the row.