&$html: HTML for the hook to add
'ImagePageFileHistoryLine': Called when a file history line is constructed.
+$imagePage: ImagePage object ($this)
$file: the file
-$line: the HTML of the history line
-$css: the line CSS class
+&$line: the HTML of the history line
+&$css: the line CSS class
'ImagePageFindFile': Called when fetching the file associated with an image
page.