First, you should know that it is generally a bad idea to insert pictures
into PowerPoint by copying and pasting. You should always save the
picture to your hard drive and then Insert > Picture > From File. That
will save you many headaches in the long run.
Now for some code. Look at "Batch Insert a folder full of pictures, one
per slide" in the PPT FAQ:
http://www.rdpslides.com/pptfaq/FAQ00352.htm
It has some nice code for inserting all the pictures in a folder into
your PowerPoint, one picture per slide. I know this isn't what you want,
but if you look toward the bottom of the code, there are some options
(some commented out so you can choose the one you want) for how to resize
the pictures. If you have any facility with VBA code, you could easily
modify this to get what you want.
--David
--
David M. Marcovitz
Microsoft PowerPoint MVP
Director of Graduate Programs in Educational Technology
Loyola College in Maryland
Author of _Powerful PowerPoint for Educators_
http://www.loyola.edu/education/PowerfulPowerPoint/