<input@accept> false positive issue.

To the Service responsibles.
An old issue about Validator.we.org/nu hasn't been fixed as of now, and I
think it is preventing my page from being checked properly.

Error: Bad value for attribute accept on element input: Expected a token
character or / but saw , instead.
>From line 551, column 16; to line 551, column 439
          <input type="file" id="attachment" name="attachment[]"
accept=".jpg,.png,.bmp,.tif,.jpeg,.x-png,.bm,.tiff,image/jpeg,image/pjpeg,image/png,image/bmp,image/x-windows-bmp,image/tiff,image/x-tiff"
/>

According to the specs, the attribute @accept on element <input> can have
as value both a MIME type and a file extension, but the validator seems to
consider invalid those values beginning with a dot.
This is an old issue which was reported long ago. Please fix it.
Regards.
Andrea Rendine