txt files as avatars?

[Covarr]

I'm curious, why does the forum allow txt avatars?

 

[Heinrisch]

I guess that they allow almost anything in the avatar picture, as long as it is not offensive to anyone... important. However, I you can't upload a txt file as avatar

 

[Orc]

It's because some sites don't allow images for remote hosting.
Renaming the extension to txt (ex. poop.jpg -> poop.txt) will sometimes bypass this, allowing the image file to be used as an avatar.