If you set a specific paper size and the content that you are trying to export to PDF exceeds the size of the paper, the content is cut off. The RadClientExportManager needs to overflow this content to a new page. This functionality would be consistent with the RadGrid's PDF export capabilities. Without it, the RadClientExportManager is only useful for generating PDFs IF one knows the exact size/dimensions of the content being exported.
Similar to how Client Export Manager can export a Multi Page to multiple pages in a PDF, would like the same functionality for Image Gallery.