Checkbox in UITableView change and revert images

I have a tableView with custom tableViewCell. Each cell has an image on the left (see screen 1). The custom tableViewCell has been subclassed. Every row has a different image which depends on indexPath.row

If I click on the image(s) the screen, the images should change to tick boxes so user can multiselect (see screen 2). If I click back on the image with a tick, it should revert back to old image on screen 1.

Issue : I know how to change the image to tick mark but don't know how to go back to old image (pls remember every row has a different image - so the "else" part in my below code will not make sense).

Below is my code to change and revert the image

@IBAction func imageTap(sender: AnyObject) {    
    let imageView : UIImageView! = sender.view! as! UIImageView
    if imageView.image != UIImage(named: "Oval 5"){
        imageView.image = UIImage(named: "Oval 5")
        awardBadge.hidden = false
    }
    else // Need to figure out how to go back to same image
    {
        imageView.image = UIImage(named: "Oval 1") 
        awardBadge.hidden = true
    }
}