Write some Software

What I have doed myself is (see attachment): 1, I load a 32-bit-depth PNG file (1 pixel 4 byte) into a byte array. 2, I manipulate the byte array thus changing the pixels. so far everything works... but what I can't seem to do is: 3, Take this manipulated byte array and save it back into a new PNG file. So in short, your task is to write me a code snippet, a function, that 1, takes a byte array (containing the pixel data of a loaded 32 bit depth PNG file) 2, takes a string containing the Directory bath + the file name of the new png file. 3, creates this 32-bit-depth PNG file in the specified directory. The code should be as simple and clean as possible. Nothing too fancy... I am a newbie programmer and would love to easily understand it. Thank you.