How to keep the pixel values same for writing an image

In attach picture the pixel matrix D is written as an image but if i read the same image from the written one I found that all pixel values except zero are converted to 255. Why this is happening? Is there any solution to keep the pixel values same after writing it?

Answer 1

[Walter Roberson]

imwrite(uint8(D), 'd.png')

Answer 2

[rcjr15]

Hi Shamim, Try using this: imwrite(YourImage, 'YourFile.jpg', 'mode', 'lossless') if you want to write it as JPEG file.

Or you can use PNG or TIFF extension which are lossless compression standards.