!! end
+!! test
+Custom class
+!! input
+[[Image:foobar.jpg|a|class=b]]
+!! result
+<p><a href="/wiki/File:Foobar.jpg" class="image" title="a"><img alt="a" src="http://example.com/images/3/3a/Foobar.jpg" width="1941" height="220" class="b" /></a>
+</p>
+!! end
+
!! article
File:Barfoo.jpg
!! text