Problem: 🥛 (http://mercury.picoctf.net:48380/)

File: THE_FILE

Solution:

Going to the site you can see an image of a man getting slapped with milk when you move your mouse.

Looking at the js and css you can see how it works. Looking at http://mercury.picoctf.net:48380/concat_v.png

This is the large image they use to make it work.

Checking the file

binwalk concat_v.png

strings concat_v.png | grep pico

exiv2 concat_v.png

zsteg concat_v.png

no-alignment

Flag: picoCTF{imag3_m4n1pul4t10n_sl4p5}