`img` element with `lang` attribute: language of the image itself?

[xandy]

(I'm interested in HTML 4.01 and HTML5, if there should be differences) Does the \[code\]lang\[/code\] attribute on an \[code\]img\[/code\] element apply to the \[code\]src\[/code\] attribute, too? Or is it only for the \[code\]alt\[/code\] and \[code\]title\[/code\] attributes?Example:\[code\]<img src="http://stackoverflow.com/questions/12622604/example.png" alt="a red foobar" lang="en" />\[/code\]Is the image "example.png" considered to be in English? (think of screenshots of a forum thread, or a graphical representation of a word, or a scan of a document)If it's true, images with non-linguistic content would need to get \[code\]lang="zxx"\[/code\]. But that would apply to the \[code\]alt\[/code\]/\[code\]title\[/code\] attributes, too, which would be incorrect.