NSString *path = [[NSBundle mainBundle] pathForResource:@"SomeFile" ofType:@"jpeg"];
NSURL *url = [NSURL fileURLWithPath:path];

NSString *docsDir = [NSSearchForDirectoriesInDomains(NSDocumentsDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *plistPath = [docsDir stringByAppendingPathComponent:@"Files.plist"];
NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:[url absoluteString] forKey:@"SomeFile.jpeg"];
[dict writeToFile:plistPath atomically:YES];

NSArray *files = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:[[NSBundle mainBundle] bundlePath] error:NULL];
for (NSString *fileName in files) {
    NSString *path = [[NSBundle mainBundle] pathForResource:fileName ofType:nil];
    NSURL *url = [NSURL fileURLWithPath:path];
    // do something with `url`
}

NSString *path = [NSBundle mainBundle] pathForResource:@"file1" ofType:@"png"];
NSURL *fileURL = [NSURL fileURLWithPath:path]

// save it as any other object or in a dictionary:

[myMutableDictionary setObject:fileURL forKey:@"file1.png"];

- (NSURL *)URLForResource:(NSString *)name withExtension:(NSString *)ext;

let url = Bundle.main.url(forResource: "FileName", withExtension: ".xyz")