Drawing shadows.

ok, I've got some problems drawing shadows. I've read the reference but I've tried to customize it for my needs and my "drawing code" but everything fails.

Code:

gate	= [UIImage imageNamed: @"gate.png"];

			else if(field[_yField][_xField].image == gate){
				field[_yField][_xField].frame = CGRectMake(0 ,0 ,80, 10);
				field[_yField][_xField].layer.anchorPoint = CGPointMake(0.0, 0.5);
			} 
			field[_yField][_xField].center = CGPointMake(xField, yField);
			[ myImageView addSubview: field[_yField][_xField] ];
			[field[_yField][_xField] release];
			drawImage = nil;

anyone know how i can make a shadow on every image in my fieldarray?