Challenge Description
We shall start off by following the instructions. I ran wget <link> to download the file. I also opened the file in GUI, but as the challenge name suggests, this is a Steganography challenge, so there was no useful information there.
PicoCTF Hint: We know the end sequence of the message will be
$t3g0.Great! Let’s look out for that.
How pico.flag.png looks like
Running zsteg
Next, I ran zsteg <file-name> and the flag was revealed easily.
b1,rgb,lsb,xy .. text: "picoCTF{7h3r3_15_n0_5p00n_a9a181eb}$t3g0"
Check
As established earlier, the end sequence of the message will be
$t3g0. This proves that we have obtained the correct flag.
Flag
picoCTF{7h3r3_15_n0_5p00n_a9a181eb}