Description:
------------
When certain types of files are uploaded, including .MPGs, getimagesize() 
incorrectly identifies them as ICOs with a MIME type of 
'image/vnd.microsoft.icon'. 

I suspect certain files probably have embedded icons in them, which is what PHP is 
detecting and reporting, but the actual file isn't an ICO.

A ~500K sample file can be found here:  
http://www.smugmug.com/img/video/problem/php-getimagesize.mpg


Expected result:
----------------
I'd expect FALSE to return, since this isn't a picture and isn't a valid type PHP 
knows about.

Actual result:
--------------
It returns this array:

array(0 => 45,
1 => 82,
2 => 17,
3 => 'width="45" height="82"',
'bits' = 65023,
'mime' = 'image/vnd.microsoft.icon');