Hello,
After an image is read into MATLAB, it is stored as a matrix of numbers. These numbers determine the color of the pixel corresponding to that index. Different kinds of images are stored differently. For example, grayscale images may be stored as an NxM matrix whereas color images can be stored as an NxMx3, since values are needed for each the red, green, and blue components.
To move a pixel, you need to copy the values from one index to another. Consider the following example of swapping two pixels in an image:
% Want to swap pixel at (x1,y1) in image with the pixel at (x2,y2)
I = imread('face.jpg');
x1 = 25;
y1 = 25;
x2 = 25;
y2 = 370;
% Get pixel data from image
pixel1 = I(y1, x1, :);
pixel2 = I(y2, x2, :);
% Swap pixels
I(y1, x1, :) = pixel2;
I(y2, x2, :) = pixel1;
imshow(I);
In your use case, it appears that you will be determining the pixel coordinate from the real and imaginary components of complex numbers.
