When you're working with family photos, I recommend scanning the images to your computer so the original photo will be preserved. This will allow you re-size your images and add text using a image or word processing program. You can also print duplicate copies to create additional paperweights as gifts or mementos for an upcoming family reunion.
Many antique shops have a variety of photographs available for sale. I call these instant relatives. I'll often flip through boxes of snapshots and cabinet cards, looking for interesting photos to add to my collection. (I collect photos of farm houses, cats, and children holding teddy bears.) Look for images that can start a conversation. These make the best paperweights.
For a touch of whimsy, add a balloon caption that reflects a funny thought the person in the photo may have been thinking. This can transform an ordinary photograph into something truly special.