░▀█▀░█▄█░█▀█░█▀▀░█▀▀░░░█▀▀░▀█▀░▀▀█░█▀▀
░░█░░█░█░█▀█░█░█░█▀▀░░░▀▀█░░█░░▄▀░░█▀▀
░▀▀▀░▀░▀░▀░▀░▀▀▀░▀▀▀░░░▀▀▀░▀▀▀░▀▀▀░▀▀▀

[ FOR EXAMPLE YOUR IMAGE SIZE IS 2560x1440 ]

• 2560 = WIDTH
• 1440 = HEIGHT

[ CHECK YOUR IMAGE SIZE WITH EXIFTOOL ]

[ NOW CONVERT YOUR IMAGE SIZE DECIMAL TO HEX ]

printf "%x\n" 2560

printf "%x\n" 1440

• DECIMAL HEX

• 1440 05A0

• 2560 0A00

hexedit --color a.jpg

ctl + s [ FOR SEARCHING ]

[ SEARCH 05A00A00 ]

[ NOW CHANGE 05A0 T0 0A00 ]

[ FINAL HEX LOOK LIKE 0A000A00 ]

ctl + x [ FOR SAVE ]

[ AFTER SAVING OPEN THE IMAGE AND YOU WILL SEE THE BLANK SPACE. EDIT THAT BLAK PAGE USING GIMP ]

[ AS AN EXAMPLE, YOU CAN ADD COLOR,ANY TYPE OF DESIGN AND WRITE YOUR SECRET MSG ON THE BLANK AREA ]

[ AFTER ADDING YOUR SECRET MSG CHANGE YOUR IMAGE SIZE TO NORMAL 2560X1440 ]