On the one hand, you should do justice to the photos by making them big enough. On the other hand, you should resize photos according to the needs of the text on that page. Once you get photos, you have to lighten them. If you don't, they'll be a big dark blob on the printed page. It's too inaccurate.
Levels is probably the best way to fix a picture.
Lighten the photo by first pressing the auto button, then dragging the three input levels arrows right and left. Right darkens, left lightens. Then, lighten it a little more with the middle arrow. Finally, change the left Output Levels box from zero to anywhere from 10-40 in increments of ten. Only then will it be light enough.