imresize is creating negative numbers from a matrix?

I'm doing something like:

image = imread(img);
image = rgb2gray(image);
image = im2double(image);
image = imresize(image);

Throughout the code, except for the last line, every element in the image matrix remains > 0. So why is imresize throwing in negative numbers?

Answer 1

[Walter Roberson]

Default interpolation method is bicubic https://www.mathworks.com/help/images/ref/imresize.html#buxswkh-1-method

"Note: Bicubic interpolation can produce pixel values outside the original range."