Converting Dicom to Png gives dark Image.

I want to save dicom (uint 16) image to png format but image appear blank, although brain image is displayed well with imshow command

I converted image to uint 8 but the problem is same again. I have attached a zip folder with few dicom images. can anyone please help me in writing dicom image in same resolution as it appears with imshow command

I =uint8(dicomread(FileName));   
imshow(I,[]);
imwrite(I,'DTP.png');

Answer 1

[Walter Roberson]

inwrite(mat2gray(I), Filename)

[Iram Shahzadi]

Thank you... this solved my problem