Once you find or take a great photo, you'll likely want to adjust it for your purposes. You may want to crop the photo to fit in a particular space or possibly enlarge it. If you increase the photo size, it's important that you don't assume it will have the same image resolution as it does on a stock photography website. Let's say you have an image at 100 dpi. If you enlarge that photo to four times its original size, each square inch will have the same number of pixels so the photo will likely appear grainy.