Adobe InDesign CS5 - Manual (Page 246)

240 USING INDESIGN
Combining text and objects
Last updated 11/16/2011
Define caption variables
Caption variables are updated automatically when a text frame containing a caption variable is moved next to an
image. By default, the Name metadata is used for the variable type when you choose Type > Text Variables > Insert
Variable > Image Name. You can edit the Image Name variable, or you can create new variables that specify image
metadata.
1 Choose Type > Text Variables > Define.
2 Choose New to create a variable or Edit to edit an existing variable.
3 For Type, select Metadata Caption.
4 Choose an option from the Metadata menu.
5 Specify text that appears before or after the metadata, and then choose OK.