Tags: image steno

Rating:

Hint wasn't there right from the start – you could play with color data of the image to uncover this message.

So you then made them tall-er by editing metadata of images (using hexeditor or any other tool like tweakpng). Apparently all of those are perfect squares (but I made them rectangles anyway :D).

Then you extract binary data out of there:

11111101111110101111
11111011111111111111
....................
01001011100001111001

And read it by columns (top to bottom, left to right, roleplaying as Chinese is required) to get the flag.

Original writeup (http://telegra.ph/Pragyan-CTF-2018-03-04#Pictorial-mess-(300pts)).