I find matrices in Mathematica to be a little tricky. They are not strictly matrices, more like lists of lists. Here is a short example of manipulation of a 3d matrix. If we have a file of image data representing multiple images (i.e. multiple 2d matrices) we can manipulate them using the Map function. So for a set of data as follows
we use Map[Image[#,"byte"]&, data] to get
Where the function Image represents each element in the data file as a pixel, with the option “byte” specifying the data format and # representing the function argument (in this case # = data).