Swizzled UIImage imageNamed for iPhone 5

UIImage+Retina4.h

//
//  UIImage+Retina4.h
//  StunOMatic
//
//  Created by Benjamin Stahlhood on 9/12/12.
//  Copyright (c) 2012 DS Media Labs. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIImage (Retina4)

@end

UIImage+Retina4.m

//
//  UIImage+Retina4.m
//  StunOMatic
//
//  Created by Benjamin Stahlhood on 9/12/12.
//  Copyright (c) 2012 DS Media Labs. All rights reserved.
//

#import "UIImage+Retina4.h"
#import <objc/objc-runtime.h>

static Method origImageNamedMethod = nil;

@implementation UIImage (Retina4)

+ (void)initialize {
    origImageNamedMethod = class_getClassMethod(self, @selector(imageNamed:));
    method_exchangeImplementations(origImageNamedMethod,
                                   class_getClassMethod(self, @selector(retina4ImageNamed:)));
}
                                                   
+ (UIImage *)retina4ImageNamed:(NSString *)imageName {
    NSLog(@"Loading image named => %@", imageName);
    NSMutableString *imageNameMutable = [imageName mutableCopy];
    NSRange retinaAtSymbol = [imageName rangeOfString:@"@"];
    if (retinaAtSymbol.location != NSNotFound) {
        [imageNameMutable insertString:@"-568h" atIndex:retinaAtSymbol.location];
    } else {
        CGFloat screenHeight = [UIScreen mainScreen].bounds.size.height;
        if ([UIScreen mainScreen].scale == 2.f && screenHeight == 568.0f) {
            NSRange dot = [imageName rangeOfString:@"."];
            if (dot.location != NSNotFound) {
                [imageNameMutable insertString:@"-568h@2x" atIndex:dot.location];
            } else {
                [imageNameMutable appendString:@"-568h@2x"];
            }
        }
    }
    NSString *imagePath = [[NSBundle mainBundle] pathForResource:imageNameMutable ofType:@"png"];
    if (imagePath) {
        return [UIImage retina4ImageNamed:imageNameMutable];
    } else {
        return [UIImage retina4ImageNamed:imageName];
    }
    return nil;
}

@end

UIImageRetina4.h

//
//  UIImage+Retina4.h
//  StunOMatic
//
//  Created by Benjamin Stahlhood on 9/12/12.
//  Copyright (c) 2012 DS Media Labs. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIImage (Retina4)

@end

UIImageRetina4.m

//
//  UIImage+Retina4.m
//  StunOMatic
//
//  Created by Benjamin Stahlhood on 9/12/12.
//  Copyright (c) 2012 DS Media Labs. All rights reserved.
//

#import "UIImage+Retina4.h"
#import <objc/runtime.h>
#import <objc/message.h>

static Method origImageNamedMethod = nil;

@implementation UIImage (Retina4)

+ (void)initialize {
    origImageNamedMethod = class_getClassMethod(self, @selector(imageNamed:));
    method_exchangeImplementations(origImageNamedMethod,
                                   class_getClassMethod(self, @selector(retina4ImageNamed:)));
}
                                                   
+ (UIImage *)retina4ImageNamed:(NSString *)imageName {
    NSLog(@"Loading image named => %@", imageName);
    NSMutableString *imageNameMutable = [imageName mutableCopy];
    NSRange retinaAtSymbol = [imageName rangeOfString:@"@"];
    if (retinaAtSymbol.location != NSNotFound) {
        [imageNameMutable insertString:@"-568h" atIndex:retinaAtSymbol.location];
    } else {
        CGFloat screenHeight = [UIScreen mainScreen].bounds.size.height;
        if ([UIScreen mainScreen].scale == 2.f && screenHeight == 568.0f) {
            NSRange dot = [imageName rangeOfString:@"."];
            if (dot.location != NSNotFound) {
                [imageNameMutable insertString:@"-568h@2x" atIndex:dot.location];
            } else {
                [imageNameMutable appendString:@"-568h@2x"];
            }
        }
    }
    NSString *imagePath = [[NSBundle mainBundle] pathForResource:imageNameMutable ofType:@"png"];
    if (imagePath) {
        return [UIImage retina4ImageNamed:imageNameMutable];
    } else {
        return [UIImage retina4ImageNamed:imageName];
    }
    return nil;
}

@end

Apple doesn't reject apps that use method swizzling. The rejected app in the provided link swizzles 'dealloc' method, and that's clearly mentioned in Apple's email there.

For this case it should be completely OK. I already have several apps in the store using method swizzling.

@bstahlhood thanks for this... what would be the license for these snippets?