Cat

This challenge gives us an image. By enumerating through regular forensics techniques such as strings,hexdump, exiftool etc. we are able to see that there are some metadata that has been modified.

Method

By running exiftool and focusing on the metadata again, we see that the XMP licence is custom and has a name of picoCTF. Looking at it's licence, we can identify a base 64 encoded string which will be our flag.