function photoToDots( src_file, dst_file, diameter )

    % Load image and convert to gray scale
    src_img = rgb2gray(im2double(imread(src_file)));

    % Calculate the dimensions of the output image
    rows = round(size(src_img, 1) / diameter);
    cols = round(size(src_img, 2) / diameter);

    % Resize, normalize and invert the source image
    src_img = imresize(src_img, [rows cols], 'bicubic');
    src_img = (src_img - min(src_img(:))) / (max(src_img(:) - min(src_img(:))));
    src_img = 1 - src_img;

    % Create an empty destination image
    dst_img = zeros((rows+1)*diameter, (cols+1)*diameter);

    % Draw the dots
    for i = 1:cols
        for j = 1:rows
            x = i * diameter;
            y = j * diameter;

            % The size of the dot is determined by the darkness of the original pixel
            r = sqrt(src_img(j, i) * diameter^2 / pi);
            dst_img = addDot(dst_img, x, y, r);
        end
    end

    % If the output image is a png, store a transparent image.
    if strcmpi(dst_file(end-3:end), '.png')
        imwrite(zeros(size(dst_img)), dst_file, 'Alpha', dst_img);

    % Otherwise, just store a grayscale image.
    else
        dst_img = 1 - dst_img;
        imwrite(dst_img, dst_file);
    end
end

function I = addDot(I, x, y, r)

    % Determine the dimensions of the dot
    w = ceil(r) + (x - floor(x)) - 1;
    h = ceil(r) + (y - floor(y)) - 1;

    % Create a meshgrid
    [X,Y] = meshgrid(-h:h,-w:w);

    % Create the dot (the division by 2 is to smooth the edge)
    D = r-sqrt(X.^2+Y.^2);
    C = min(max(D/2, 0), 1);

     % Calculate the position of the patch in the destination image image
    X = x+X;
    Y = y+Y;

    % Calculate the indexes in the destination image
    idx = (X-1) * size(I,1) + Y;

    % Add the dot to the original image
    I(idx) = max(I(idx), C);

end