FastStone Photo Resizer. Free, use "Advanced Options" to resize by percentage.
Transformation Thread: http://forum.ttmembers.com/showthread.php?t=10536
"Only that in which is me can understand what I am saying." Baba Ram Dass
"When I let go of what I am, I become what I might be." -John Heider
"Everyone is a Being. Not everyone is a Becoming."