I took a payload which I wanted to have the target execute on their system. encoded it using base64 encoding and appended it to a image's exif data to bypass antivirus scanners scanning the exe.
To embed the encrypted payload use:
exiftool "-comment<=/Users/yallah/Documents/encrypted_payload.py" /Users/yallah/Desktop/image_of_choice.jpg
python script used to extract the payload from exif and decrypt before exec is in py file.