I found, that it is possible to change gamma in Dopus Viewer(View -> Gamma Correction), so I would like to know if it is possible to apply new gamma to the image, in other words to save the corrected image? I tried to save it via file menu(File->Save as) and Dopus doesn't save gamma correction, unlike "image rotation".
Ok, I just thought that if Dopus is saving image rotation then it is also saving gamma correction. But if this function works as a temporary filter - it is fine too, I am using other tools for photo editing purposes anyway.