Hi Jackie,
To draw a fancy border, you would need to replace the zero-padding with whatever pattern or color you desire.
One way to do this would be to add a border around the existing image. I will go through a short example where we first create an initial image containing the entirety of our border and then overlay our actual image on it. I'll go with a black and white checkered border for this example.
%read the image and get its dimensions
i = im2double(imread('autumn.tif'));
[nrows,ncols,~] = size(i);
%10px border on all sides, so we increase the border size by 20px in both dimensions -- start with all black for now
x = zeros(nrows+20,ncols+20,3);
%create a checkered border by alternating between white and black pixels
x(1:2:226,1:2:365,:) = 255;
%fill our image in the middle of the larger matrix
x(11:end-10,11:end-10,:) = i;
%image now has a checkered border
image(x)
If you want a border that isn't a regular pattern, I suggest creating each strip separately, then concatenating them all together as a larger matrix. I hope this helps!
