Making Your Photos Smaller (Downsizing)
There is a different set of rules we use for maintaining as much quality as possible when making an image smaller, and there are a couple of different ways to do just that (we’ll cover the two main ones here). Luckily, maintaining image quality is much easier when sizing down than when scaling up (in fact, photos often look dramatically better—and sharper—when scaled down, especially if you follow these guidelines).
Downsizing photos where the resolution is already 300 ppi:
Although earlier we discussed how to change image size if your digital camera gives you 72-ppi images with large physical dimensions (like 24x42″ deep), what do you do if your camera gives you 300-ppi images at smaller physical dimensions ...