CGRect Center for Ipad

Assuming image is of type UIImage then:

CGRect imageFrame = CGRectMake(
    CGRectGetMidX(self.view.frame) - (image.size.width / 2.0),
    CGRectGetMidY(self.view.frame) - (image.size.height / 2.0),
    image.size.width,
    image.size.height);

Assuming imageView is of type UIImageView then:

CGRect imageFrame = CGRectMake(
    CGRectGetMidX(self.view.frame) - CGRectGetMidX(imageView.frame),
    CGRectGetMidY(self.view.frame) - CGRectGetMidY(imageView.frame),
    CGRectGetWidth(imageView.frame),
    CGRectGetHeight(imageView.frame));

You don't need to calculate the centre point, as it's available for a view anyway:

CGRect superviewBounds = superview.bounds;
imageView.center = CGPointMake(CGRectGetMidX(superviewBounds), CGRectGetMidY(superviewBounds));