Speed up Operations in Photo-laden Pages Files
Here's a simple speed-up tip for working with photo-laden documents in Pages. If you work with such documents, especially on older and/or memory-challenged Macs, you may find yourself looking at the spinning rainbow cursor entirely too often, such as after any little minor change, or when navigating from page to page.
If that's the case, then try this simple fix: disable the page thumbnails that appear in the left-hand column of your document. Select View -> Page Thumbnails (or press Command-Option-P) to disable them--you should see a checkmark there to indicate that the thumbails are enabled.
Once disabled, scrolling and making changes should be much snappier. Even on a faster Mac, I've noticed that Pages seems generally more responsive with the thumbnails disabled. The downside of this workaround, of course, is that you don't have the thumbnails available for speedy navigation around your document. Given there's a keyboard shortcut, though, it's easy to toggle them back on when you need to see them, then toggle them off again when done.