This is a 50 points task in PicoCTF to solve this puzzle. I have to admit that I sat on it for a while because I suspected a complex solution like using stenography or any other hidden clues in the image file. Finally I just sat down and it became obvious immediately.
To solve this puzzle you have to download an image file and investigate it.
If you look at the numbers and the curly braces it will be immediately obvious!
A=1 B=2 C=3 ... Y=20
If you write it up with the letters you can get the flag!
If you want to discuss the topic with other technology-minded people, join my Discord: https://discord.gg/YbSYGsQYES
Now we have an IRC channel as well: irc.libera.chat / #tomsitcafe
Tom's IT Cafe 