An image that has been translated from its original language into something else.
Specifically, use this tag when the text on the image itself has been changed to another language, i.e. it was "hard translated", as opposed to "soft translated" with overlay boxes (notes.)
Some people may use the word "typeset" as opposed to "hard translated," but they both mean the same thing - somebody went onto an image editor, erased the original text, and put the translated text on.
As this tag is generally used for English-language pictures, and is used by people to find them, images that were originally in English should also receive this tag in order to make searching for them easier.