About JPG Optimization
JPG or JPEG stands for Joint Photographic Experts Group - and refers to a Standard for Compression of picture type information. There are a lot of variations of how it is actually implemented. As a result, not all JPG Viewers can display all JPG files. One type, called progressive JPG, can not be displayed in Real Player. Using JPEGTRAN to optimize a file can remove the 'progressive' part and leave a JPG Real Player can display. If you know your Show will only be displayed in Web Browsers, optimization is usually not necessary.
RPWiz can automatically make optimized JPG files for you.
If by chance you are actually Streaming your SlideShow, because of the variation in compression, not all JPGs stream well either. JPEGTRAN also improves the ability to Stream JPG files. See About Bit Rate for more information.