Image scaling is the process of changing the size of a digital image. Scaling is a non-trivial process that involves a trade-off between speed, smoothness and sharpness. When increasing the size of images, the fact that digital images are made of pixels becomes particularly evident. An image size can be changed in several ways. Consider doubling the size of following image: The most easy way of doubling its size is to replace every pixel with four pixels of the same color.