Saving and reopening the image reveals a hidden string or a URL at the very bottom of the extended canvas. 4. Decoding the Final Payload Depending on the specific version of this challenge:
The string found at the bottom of the image (after fixing the height) is often encoded in Base64 or ROT13 . 5. Flag Extraction Decoding the discovered string reveals the flag format: 17199 d3j4.rar
Locate the 4-byte height value and increase it (e.g., from 00 00 02 00 to 00 00 04 00 ). Saving and reopening the image reveals a hidden
The challenge relies on steganography or a hidden IDAT chunk tweak. Use a hex editor (like HxD or 010
Use a hex editor (like HxD or 010 Editor) to view the PNG's IHDR chunk .
The "Deja Vu" hint often refers to the fact that the image's height has been tampered with to hide data at the bottom (a common CTF trope).