I just use Paint, open the photo, click edit to open it in paint, go across the the 'image' menu and select stretch/skew. From there you can reduce the overall size of the picture, without losing quality, as long as you don't make it bigger.
Ie, if you want the picture 1/2 the size, enter 50 and 50, this will reduce each dimension by 50%, giving you a small pic, but the same pixels.