MATLAB: How to use imwrite command for manually save image

Question

I want to make a simple program that ask image file from user, resize it and then it ask from user where to save it. Everything went right except this imwrite command. i dont know to use it properly . below is the code.

clc;
clear all;
close all;
getimage=imgetfile();
x=imread(getimage);
figure(1); imshow(x); title('1024*1024 Image')
y=imresize(x,[512 512]);
figure(2); imshow(y); title('512*512 Resized Image');
[filename, pathname] = uiputfile('*.jpg', 'Save Picture as');
imwrite([y, filename, pathname]);

Answer 1

file=fullfile(pathname,filename)
imwrite(y,file);