Techniques are provided to enable quick previews of what a modified document would look like. In an implementation, a set of page images are stored. Each page image represents a page of a document, the page having been converted to a page image for a first version of the document to permit the document to be viewed in a viewer program. A command is received to modify the document. The requested modification may include, for example, reordering pages, deleting pages, or extracting pages. A preview is generated for a second version of the document. The preview reflects the modification and uses at least one page image from the set of page images created for the first version of the document. Reusing page images allows the preview to be generated very quickly.