Hi HDB,
No, the macro won't do anything with pics you've already inserted - it does all the insertion and structuring itself. Accordingly you may find it easiest to delete the pics you've already inserted and let the macro do the lot. Try the macro on a test document first, though, to confirm it does what you're after.
For PC macro installation & usage instructions, see:
http://www.gmayor.com/installing_macro.htm