When to use caption commands teachers/how-to/Pages/insert-caption (video)
With the caption commands, you can automatically insert labels, such as Figure 1 or Table 1. Word 2007 keeps track of the numbering. For convenience, you can also enable AutoCaption (which automatically inserts a caption when you add a picture or table). You can also quickly insert a table of all the figures in your document, or add a text box over a picture so that the caption and picture can be moved together.
Way too much detail about keeping captions with pictues: keep-with-caption
