You know the deal- you just put 300 pictures on your computer after your vacation, and they all have meaningless names like DSC_W32355whosyerdaddyblah.jpg
So organize them into folders with sensible names like 2011Jan15 Ski Trip (doing the date this way will keep all your years of image folder in order!). This short cut shows you how to then name all the files with one format (so each picture becomes 2011Jan15 Ski Trip (1)... (2) and so on. This is a Godsend. Exercise caution if the existing names have meaning (i.e. ch1, ch2) as that'll be gone gone gone... when in doubt duplicate your folder before you play.