Java project -- 2

I'm working on a personal program in order to research steganography. I have existing code in 6 classes but I need 2 modified to do what I want it to do. I need someone good in java with some understanding of steganography to help me make my modifications and make the program operational as required. Some items work and others work but not as intended.

Expected functionality:
1) Embed a text in an image (steganography)
2) Split the image with embedded text into 4 parts
3) Extract the text fragments from the individual 4 images.

Tried methods that need work
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1) Split images into 4 parts (However we are unable to extract the embedded text from them individually)
2) Split the byte stream into 4-byte arrays and tried to save them as images (but here we are unable to save them as images)