LEADTOOOLS supports a number of Multipage File Formats. When loading a multipage file, you can load all pages or only one of the pages. The SAVEFILEOPTION specifies extra options for writing an image file.
To append an image to a file, create a SAVEFILEOPTION structure and pass it as the last parameter to any LEADTOOLS Save function. Set the PageNumber field equal to 2^sizeof(int) - 1 to be sure that each page is appended.
Splitting a Multi-page TIFF File (API)