You need to learn about loops.
NSMutableArray *photos = [[NSMutableArray alloc] init];
NSString *filePath = @"/Library/Application Support/Testing/Testing";
NSArray *myArray = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:filePath error:nil];
for (NSString *filename in myArray) {
NSString *fullPath = [filePath stringByAppendingPathComponent:filename];
MWPhoto *photo = [MWPhoto photoWithFilePath:fullPath];
[photos addObject:photo];
}
BTW - this code will only work in the simulator since you are hard coding the library path.
This code also assumes that the only files in the directory are image files.