$('.imgset1 img').imgCentering();	//centering only no stretch

$('.imgset2 img').imgCentering({
	'forceWidth': true,		//centering with fix width
	'bgColor': '#000'		//empty space color
});

$('.imgset3 img').imgCentering({
	'forceHeight': true,		//centering with fix height
	'bgColor': '#000'		//empty space color
});

$('.imgset4 img').imgCentering({
	'forceSmart': true		//centering without showing background
});