Noob needs program

[E.T.]

Hey all,
Im looking for specific recommendations for an imaging program to manipulate [make bigger/smaller] the pixel size of my digital photos.
I have not a clue as to what that ability is called, or what is possible, so shopping for such has left me confused.

Ive attached an example of a digital photo I would like to reduse the size of [pic is 640x480 pixels]. I dont know if its possible, but are there imaging programs that can reduce this picture down to say, 80x80 pixels or so?

Thanks for help.
E.T.