Covert to PNG or help me in reading a .gif image

I am working with Harvard Medical School MRI images , and these images are gray and in .gif format. When I use imread() and then imshow() functions, the images are not appearing as it is seen in the website or in desktop.

I asked the question they asked me to change the format to png. How can I change format to png in matlab as a gray image without losing information . I tried imread() and imwrite( gif), it can not solve the problem. I attached some images herewith.

Answer 1

[Image Analyst]

Use ind2rgb.

fileName = '1.gif';
[img, colorMap] = imread('1.gif');
rgbImage = ind2rgb(img, colorMap);
grayImage = rgb2gray(rgbImage);
imshow(grayImage, []);
% Save as png
fileName = strrep(fileName, '.gif', '.png');
imwrite(grayImage, fileName);
% Recall to test that it saved it correctly
figure
img = imread(fileName);
imshow(img, []);

[Sanjib]

Thank you so much.