My eyesight is pretty bad even with glasses. I looked at it for a few minutes today on Yahoo and saw something at the bottom right that kind of looked like a face. Not sure.

Can't have light without the dark, so why leave him out?

I can't find anything btw.

X marks the spot,
there is a hidden agenda in this article

Try this. Look to the bottom right of the clouds:

It appears to me that someone in the past, our past and not the painting's, redid the clouds or added the clouds! If you let your eyes view the entire scene and focus on just the white portions it clearly shows the clouds as being a different color white than the white used with the rest of the painting.

Was there damage that needed repairing?

Was there another image there that needed covering up?

Even the hem of the outfit of the angel closest to the face has an anomalous sort of rope-like shadowing next to his leg, as if it were the edge of the cover-job!

The face is clearly there, I am shocked no one noticed it before, but really this looks like a very bad re-do on the paint as it does not match at all!

The figure is difficult to see from the floor of the basilica but emerges clearly in close-up photography.

Sergio Fusetti, the chief restorer of the basilica, said Giotto probably never wanted the image of the devil to be a main part of the fresco and may have painted it in among the clouds "to have a bit of fun."

The master may have painted it to spite someone he knew by portraying him as a devil in the painting, Fusetti said on the convent's website.

from the OP link

Strain as I might, I'm just not seeing it.

This is what they say is the devil found in
detail of Giotto fresco.

Wow people see what they want to see, I understand that faces are the most recognizable feature when we look at nature or other objects. Take me for example; when I wait for my train home, I usually zone out, and stare at the ground with or without music... and the ground looks like it's moving. When I focus in on it, it all stops, then I'll look at other things at the station, and again they move or form recognizable features. eyes, faces, ears.

If I saw what I think I saw in that painting... then the devil has a mustache, lol.

Satan is the most beautiful angel. How often they seem to forget that.