I will begin by explaining various aspects about image resizing: how it works, what the important problems are, who would be interested in this. I?ll continue by comparing several existing methods. Finally I?ll conclude with the best method to use.How does enlarging work? Upsizing an image increases its resolution (size in pixels/points). To do this, information from the original image is used to create the enlarged version. Imagine a grid of pixels in a plane. In the original image they are all side by side. Enlarging the image means enlarging the grid. The more you stretch it, the more separated the pixels become. Those pixels in-between need to be filled-in. This is called interpolation. There can be other steps after interpolation.Problems that need to be solved by upsizingOne of the problems that appear is that for small ima electronic store ges pixels on the edges may be aliased. This becomes more apparent when enlarging. This is the jagged edges problem that many upsizing methods try to overcome. In one extreme you have edges that are sharp but jagged in another smooth but blurry. A compromise between smoothing an edge and keeping it sharp is searched for. Over-smoothing to maintain sharpness is not that hard to obtain but this creates an unrealistic look to images. Another problem is loss of detailed texture in the upsized image. The only method that even considers this is reshading.When is upsizing an image useful? Increasing the size by 200% means transforming a 3 megapixel (MP) image into a 12 MP one. If something like this can be created without losing quality then using an average camera and upsizing it would be almost the same as using a professional camera.