I am reading the lena pgm file in java with that sample code to read / write.

the first thing I noticed is that some values are way above 255 and are like 8445....... why is that ?

the other thing is that for test purpose , I just read values and write them to another file , and when I open that new created file- that was created by the same values as the first one - the picture is significantly different , why is that , I have not changed any values just wrote it to a different file.