Need help with shrinking images.

[Coarse]

So, yeah, I need an image shrinker that doesn't change the color tone of my photos unlike FastStone.
My cousin had one, but I forgot what was the name of the program, and I can't ask him now since he's not online nor do I have any of his contact numbers.

[Exile]

Photoshop, GIMP, ect.
How small do you need it shrinked?