A picture is nothing but a collection of pixels. So what is a pixel, then? A pixel is actually the smallest element of a picture. We can’t break pixels to mini pixels and so on. It is also the smallest element in the picture which can be edited i.e. changing colors etc. Say there are two points A1 with coordinates (2.2, 2.7) and A2 with coordinates (2.6, 2.7) then both these points will be represented by only one pixel (2, 3). Thus, there can be an infinite number of points in this pixel (2,3) or in any given pixel. That means we surely can’t edit these points but we surely can edit the pixel.