Why some mpg files have icon preview (and quiclook) and others mpg files don't?

Just a guess, from me, as an answer.

There are two different formats that use the .mpg file extension (MPEG-1 and 2). On my machine MPEG-2 files don't show an image from the file whereas, MPEG-1 files do show an image.

But to add to the confusion my MPEG-2 files show the QuickTime icon and MPEG2 letters and number and yours shows just MPEG. But the file name (M2U00111) suggests it is MPEG-2 format.

This is the normal icon I see on my Mountain Lion machine for an MPEG-2 file and it is different on your machine. I don't get a "preview" of the file or any "QuickLook" option on my MPEG-2 files.

Since Mountain Lion is the first release of any Mac OS that includes "native support" for MPEG-2 formats (previous OS's had to purchase a $20 component) I guess you and I will live without icon previews or "QuickLook" options on these few MPEG-2 files we may come across.

Hi lucadl, sorry for my english. I have the same problem as you, and I work with video edit and I find very helpful to show video icon preview at finder before import them, and in mpg case it doesn't want to do it. Thanks!