Why won't my random image generator act randomly in xcode?

Question

I'm trying to display a random image from 3 possible images. The problem when I try to load it in the simulator is it only seems to be displaying one of the three. In this scenario it's only showing case 1 every time.

{

int randomimages = rand() %3;
switch (randomimages) {
    case 0:
        Background.image = [UIImage imageNamed:@"BGK11.png"];
        break;
    case 1:
        Background.image = [UIImage imageNamed:@"BGK12.png"];
        break;
    case 2:
        Background.image = [UIImage imageNamed:@"BGK100.png"];
        break;
}

i declared a IBOutlet UIImageView *Background; in the .h

Do I need to seed the integer differently? I'm not sure what is going wrong.