Conflicting mime types

Jerome Leclanche adys.wh at
Tue Mar 5 04:41:24 PST 2013

I.. don't even know what to say.

If they are invalid PNGs then they should not be a child of image/png.
However they shouldnt register the *.png glob either as a glob implies "You
can somewhat safely assume such a file is of this mime type".

With that said, I don't think such a mime type has a place in
 - It's not an officially recognized mime type in any way
 - It's was likely originally intended to be a valid image/png
 - It's an implementation-specific bug/workaround/detail
 - PNG is a massively popular file format, who the hell thought this was a
good idea?


J. Leclanche

On Tue, Mar 5, 2013 at 12:22 PM, Thomas Kluyver <thomas at>wrote:

> On 5 March 2013 11:58, Jerome Leclanche <adys.wh at> wrote:
>> Are they valid PNGs? If so, it sounds like the mime type should just be a
>> child of image/png and drop the glob here.
> It's not clear, and I don't have one to examine. I would guess that
> they're not valid:
> - The commit message where the mimetype was added described them as 'Apple
> broken PNGs'
> - An Apple Q&A page says that 'Preview' (the OS X image & PDF viewer)
> can't open "iOS-optimized" PNGs. (Just Works</sarcasm>)
> Thomas
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the xdg mailing list