AxPoint generates beautiful slideshows in PDF format from a simple XML description format. It is written as a Perl SAX2 handler, but also ships with command line tools. The format supports slide transitions, PDF bookmarks, bullet point transitions, images, text colours, different fonts, and more.
ExifTool is a platform-independent Perl library plus a command line application for reading, writing, and editing meta-information in image, audio, and video files. It supports many different types of metadata including EXIF, GPS, IPTC, XMP, JFIF, GeoTIFF, ICC Profile, Photoshop IRB, FlashPix, AFCP, and ID3, as well as the maker notes of many digital cameras.