Fix corruption of png files about steganographerpy HOT 3 CLOSED

PNG technical details
The png Module

from steganographerpy.

When saving with PIL it is changing the data that is in the file after the message is added, causing the message to be lost. Need to save the file with PIL first with no changed. Open the file again so it is now in a format that PIL won't radically change. Add the message and save it out as normal.

The problem is if you open a file with PIL and save it back out with no changes it is still a different file because PIL created it. But if PIL made the file first and then opens and saves with no changes, it is the same file. There needs to be a one to one connection between opening and saving or the bit manipulation to hide a message will be lost.

from steganographerpy.

Images are now correctly handled. The only issue is that the files are not identical with some slight bit changes only. This is because the files are opened and then saved by PIL. PIL doesn't respect what the file originally had, unless the original file was already created by PIL.

from steganographerpy.