UIImage+Shadow.m

@interface UIImage (Shadow) 

+ (UIImage *)imageWithContentsOfFile:(NSString *)path withShadow:(BOOL)applyShadow;

+ (UIImage *)imageNamed:(NSString *)name withShadow:(BOOL)applyShadow;

+ (UIImage *)applyShadow:(UIImage *)theImage;

@end

@implementation UIImage (Shadow)

+ (UIImage *)imageWithContentsOfFile:(NSString *)path withShadow:(BOOL)applyShadow {
	UIImage *image = [UIImage imageWithContentsOfFile:path];
	if (!applyShadow) {
		return image;
	}
	
	return [UIImage applyShadow:image];
}

+ (UIImage *)imageNamed:(NSString *)name withShadow:(BOOL)applyShadow
{
	UIImage *image = [UIImage imageNamed:name];
	if (!image) {
		return image;
	}
	if (!applyShadow) {
		return image;
	}
	
	return [UIImage applyShadow:image];
}

+ (UIImage *)applyShadow:(UIImage *)theImage
{
	UIGraphicsBeginImageContext(CGSizeMake(theImage.size.width + 12, theImage.size.height + 12));
	CGContextSetShadow(UIGraphicsGetCurrentContext(), CGSizeMake(6.0f, -6.0f), 6.0f);
	[theImage drawAtPoint:CGPointZero];
	UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
	UIGraphicsEndImageContext();
	
	return result;	
}

@end

Adds a shadow to an UIImage