A guide to digital image resizing

Digital Image Resizing: "One aspect of digital images which seems to cause a lot of confusion to beginners is the matter of image size. There are three basic measures of image size - Pixel count - e.g 3000x2000 pixels, -Physical size - e.g. 4' x 6', -Resolution - e.g. 72 pixels per inch (ppi)" (found at PhotographyBLOG)