This question already has an answer here:
David has a profile picture of a smiling face:
However, in questions or answers, the smaller version of this image shows up with a strange grey corruption at the bottom, blocking the smile:
The image returned for the thumbnail is
Why is this? Is there an error in the thumbnail creation process?*
* If there is a bug, I suppose the problem is with Imgur, but perhaps ye could pass it onto them?