When the matrix size of a digital image increases, what happens to the size of the individual pixels?

When the matrix size of a digital image increases, the size of the individual pixels decreases. This occurs because the total number of pixels in an image is determined by both its matrix size and its physical dimensions. When you increase the matrix size (for example, by increasing the number of rows and columns in the array that represents the image), you are essentially subdividing the same physical space into more sections. Each section corresponds to a pixel, which means that as you add more pixels, each one must occupy a smaller portion of the total area of the image.

To illustrate, if you have an image that is 1000x1000 pixels and you increase the matrix size to 2000x2000 pixels while keeping the physical size of the image constant, each individual pixel shrinks because there are now more pixels sharing the same amount of physical space. This results in smaller pixel dimensions, hence the correct answer highlighting that the size of the individual pixels decreases.