last_photo_taken.m

ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
    [library enumerateGroupsWithTypes:ALAssetsGroupSavedPhotos usingBlock:^(ALAssetsGroup *group, BOOL *libraryStop) {
        NSInteger assetCount = [group numberOfAssets];
        NSIndexSet *indexes = [NSIndexSet indexSetWithIndex:assetCount-1];
        [group enumerateAssetsAtIndexes:indexes options:NSEnumerationReverse usingBlock:^(ALAsset *result, NSUInteger index, BOOL *groupStop) {
            if(result){
                CGImageRef imageRef = [[result defaultRepresentation] fullResolutionImage];
                UIImage *image = [UIImage imageWithCGImage:imageRef]];

                // Do stuff with the image.
            }
        }];

    } failureBlock:nil];