Can’t insert custom field key titled “image”

I can no longer save a custom field key with the name of “image”. Any other name seems to work fine, but when I attempt to update the post with a custom key titled “image”, it never shows that it saves the url I enter as the value. The image custom key just will not be saved.

Prior to updating to version 2.8.2, and making a few other changes to my template files, this worked fine.

Has something changed that I am not aware of? Are there certain words that you can’t use for custom field names now?