This will allow you to take a screenshot of a UIView, but more importantly only a section of that view

Screenshot.swift

//
//  Screenshot.swift
//
// 1) Take a picture of a UIView
// 2) Take a picture of a UIView's subframe. EG. Fullscreen UIView with a
//     small square box in the middle, it will only save what's visible in the box frame
//     but not the box itself

import Foundation
import UIKit

extension UIView {
    
    class func image(view: UIView, subview: UIView? = nil) -> UIImage? {
        
        UIGraphicsBeginImageContextWithOptions(view.frame.size, false, 0)
    
        view.drawHierarchy(in: view.frame, afterScreenUpdates: true)
        
        var image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!

        UIGraphicsEndImageContext()
        
        if(subview != nil){
            var rect = (subview?.frame)!
            rect.size.height *= image.scale  //MOST IMPORTANT
            rect.size.width *= image.scale    //TOOK ME DAYS TO FIGURE THIS OUT
            let imageRef = image.cgImage!.cropping(to: rect)
            image = UIImage(cgImage: imageRef!, scale: image.scale, orientation: image.imageOrientation)
        }
        
        return image
    }
    
    func image() -> UIImage? {
        return UIView.image(view: self)
    }
    
    func image(withSubview: UIView) -> UIImage? {
        return UIView.image(view: self, subview: withSubview)
    }
}

THANK YOU NITRAG!

One correction for taking image over subview is to adjust the origin point too:
rect.origin.x = subview.frame.origin.x * image.scale rect.origin.y = subview.frame.origin.y * image.scale