Big thanks to MarkM

[RLBJR65]

With MS Paint,
1) Chose select as if you were going to cut the image
2) Click on the image menu and select stretch/scew
3) Reduce the horizontal and vertical settings (at the same time) from 100% to 49%.

It still takes a bit of experimenting, sometimes you have to select a slightly larger area before reducing so the pads don't squish or stretch. Especially if the board is much wider than it is tall or vice versa. It usually takes me a couple of tries to get it right. I always print on plain paper first just to make sure.

Also shrinking text does not work so well. I always redo or add text and paste it in after resizing.