PIL package (Mention: In Mac, install it by 'sudo pip3 install pillow'.)
run 'python3 GUI.py'
Instruction
This steganography tool is compitable with both 256 gray & 24 bit true color bmp files.
Apart from the first 1078 bits in header, I use the next 32 bytes to store the length of hidden message.(An int is 32 bits long, which can be hidden in 32 bytes.)
So a 256 gray bmp file with 'wh-32<=0' or a 24 bit true color bmp file with 'wh*3-32<=0' can not hide message using this tool.