[Mediawiki-l] why MIME type text/plain for .png images ?

Good Afternoon MW Fans:

OK, so which memo did I miss ? Running version 1.8.2 here.

I tried uploading some .png image files into this wiki: http://genomewiki.ucsc.edu/ and it first complained about illegal file types. I had 'png' on the $wgFileExtensions array, but that seems to have been superceded by MIME type checking. So, I momentarily inserted: $wgVerifyMimeType= false; so I could get by the illegal type warning, but then these .png images show up in the upload log as MEME type text/plain

So how do I get .png images to function ? The DefaultSettings says it is using the MIME type file: $wgMimeTypeFile= "includes/mime.types";

Which does include the png type.

So what am I missing ?

--Hiram