Powerpoint 2007 default picture folder

Hi,

First of all: I’m sorry about this ridiculous question, but….

How can I change default folder where Powerpoint, Word or Excel 2007 will look for pictures when inserting new one?

As default, it will look my pictures folder

I know, it’s somewhere in registry but don’t wont to mess up and just try. My registry is full of “My Pictures” keys or values….