Modified the is_image() method in the Upload library to take into account Windows IE 6/7 eccentricities when dealing with MIMEs
diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php
index 9d2bae2..fa1cf1e 100644
--- a/system/libraries/Upload.php
+++ b/system/libraries/Upload.php
@@ -477,17 +477,28 @@
 	 */	

 	function is_image()

 	{

+		// IE will sometimes return odd mime-types during upload, so here we just standardize all

+		// jpegs or pngs to the same file type.

+

+		$png_mimes  = array('image/x-png');

+		$jpeg_mimes = array('image/jpg', 'image/jpe', 'image/jpeg', 'image/pjpeg');

+		

+		if (in_array($this->file_type, $png_mimes))

+		{

+			$this->file_type = 'image/png';

+		}

+		

+		if (in_array($this->file_type, $jpeg_mimes))

+		{

+			$this->file_type = 'image/jpeg';

+		}

+

 		$img_mimes = array(

 							'image/gif',

-							'image/jpg',

-							'image/jpe',

 							'image/jpeg',

-							'image/pjpeg',

 							'image/png',

-							'image/x-png'

 						   );

 

-

 		return (in_array($this->file_type, $img_mimes, TRUE)) ? TRUE : FALSE;

 	}