gscan2pdf is a GUI to ease the process of producing PDFs from scanned documents. You scan in one or several pages and create a PDF of selected pages. Scanning is handled with SANE via scanimage. PDF conversion is done by PDF::API2. Perl is used for portability and ease of programming, with gtk2-perl for the GUI.
gtk-screenshot is a program for taking screenshots. It captures the screen or a window and saves the image in the PNG format. It is similar to gnome-screenshot but it's not a GNOME application. All parameters may be specified on the command line, or the application can be graphicaly driven.