I have published newspapers and am currently publishing a magazine here in New York. The size of the photo does not really matter. It is the quality. The paper will resize and crop (cut pieces of it off) the photo to meet their needs.
Maybe you already know...
If the paper is B&W (black & white), make sure you send them a B&W photo. If you have color shots, have the B&W conversions made on your end so you can see the final product.
Don't skimp on repros. Get the best possible shot. Newspaper is very unfriendly to photos so you want to have everything going for you.
Do not send negs (negatives). It is a pain in the a** for the paper and may get you bumped.
Make sure the importand photo content is in the center of the photo. Papers and magazines will almost always crop of photo so you want to be sure that what you want people to see is in the center.
Make sure that the photo you send is larger than what will appear in print, never smaller. When a photo is reduced it often becomes crisper. When it is enlarged it can become grainy or blurry.