Wall Heater by a window ...is it ok?

This installation is in a garage…the buyer wanted to know if the heater by a window is a correct installation…( would there be backdraft problem )

http://i187.photobucket.com/albums/x296/dawlita/Nachi/072.jpg

http://i187.photobucket.com/albums/x296/dawlita/Nachi/017.jpg

You can secure the the window shut but it looks like you are not high enough to meet the 18" rule for garages with regard to flammable vapors.

Thanks