Pages are a boon to Fireworks since their introduction
in CS3 release. There is a built in Keyboard navigation facility for iterating through all the pages in the document of a Fireworks png file.
The ‘PgUp’ and ‘PgDn’ key does the trick of navigation. Even when the focus is on the canvas, the keyboard shortcuts will work.
Incase you are editing a field or entering some values/text in any of the panels then you will need to exit that editing field and then the shortcut will work for you. Simplest way is to click on the canvas to gain focus on the main area of the application.
This keyboard navigation is valid on Windows and Mac.