Some helpful ALAssetsLibrary helpers.

ALAssetsLibrary+CoreExt.h

//
//  ALAssetsLibrary+CoreExt.h
//
//  Created by Brian Norton on 6/14/14.
//

@interface ALAssetsLibrary (CoreExt)

+(ALAssetsLibrary *)library;

-(BOOL)canRequestAccess;
-(BOOL)authorized;
-(ALAsset *)assetNamed:(id)name;

README.md

####Photos Permission This will make sure your request for photos is ~95% certain of being approved.

By knowing that you have not asked for access yet [ALAssetsLibrary library].canRequestAccess you can ask the user if they will allow access to photos if you ask. With the addition of a blocking way to load a photo (if you're already in an NSOperation or a GCD block) you'll have all the tools you need.

If they say yes to the cheap question (will you allow access?), you can then make the expensive question (you can only ask once).

ALAssetsLibrary+CoreExt.m

//
//  ALAssetsLibrary+CoreExt.m
//
//  Created by Brian Norton on 6/14/14.
//

#import "ALAssetsLibrary+CoreExt.h"

@implementation ALAssetsLibrary (CoreExt)
 
+(ALAssetsLibrary *)library { static ALAssetsLibrary* library;
    if(!library)
      library = [[ALAssetsLibrary alloc] init];
    
    return library;
}

-(BOOL)canRequestAccess {
    return [ALAssetsLibrary authorizationStatus] == ALAuthorizationStatusNotDetermined;
    
}

-(BOOL)authorized {
    return [ALAssetsLibrary authorizationStatus] == ALAuthorizationStatusAuthorized;
}

-(ALAsset *)assetNamed:(id)name {
    NSURL *url = [name isKindOfClass:[NSURL class]] ? 
        name : [NSURL URLWithString:[NSString stringWithFormat:@"%@", name]];

    __block ALAsset *asset; dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

    [[self.class library] assetForURL:url resultBlock:^(ALAsset *incoming) {
        asset = incoming;
        dispatch_semaphore_signal(semaphore);
    } failureBlock:^(NSError *error) {
        dispatch_semaphore_signal(semaphore);
    }];

    dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);

    return asset;
}