Pros and cons of where to store image data

[peter9.smith at ps.ge.com]

I'm still on the newbie learning curve so bear with me.  If you want to have
an image on a card you have two choices as to where to store the image data?
Either inside the image itself or in an external file?

Assuming that's correct what are the pros and cons?  If you hold the image
data inside the card is it compressed in the stack file?  I'd prefer to hold
the image data inside the card as that should be faster loading the stack.

Thanks for any help, Peter Smith.