Problem
Can you unzip this file and get the flag?
Hint
put the flag in the format picoCTF{XXXXX}
Solution
The title says to unzip the given file. The following does this.
$ unzip flag.zip
$ xdg-open flag.png
xdg-open lets you open files from the terminal instead of manually clicking it. The flag is inside the png.
Flag
picoCTF{unz1pp1ng_1s_3a5y}