新增onlyReturnAsset属性，为YES时选择器不获取大图，只返回asset出去

TZImagePickerController/TZImagePickerController/TZImagePickerController.h

@@ -102,6 +102,10 @@
 /// 默认为YES，如果设置为NO, 选择器将不会自己dismiss
 @property(nonatomic, assign) BOOL autoDismiss;
 
+/// Default is YES, if set NO, in the delegate method the photos and infos will be nil, only assets hava value.
+/// 默认为NO，如果设置为YES，代理方法里photos和infos会是nil，只返回assets
+@property (assign, nonatomic) BOOL onlyReturnAsset;
+
 /// The photos user have selected
 /// 用户选中过的图片数组
 @property (nonatomic, strong) NSMutableArray *selectedAssets;

TZImagePickerController/TZImagePickerController/TZPhotoPickerController.m

@@ -352,9 +352,17 @@ static CGFloat itemMargin = 5;
     }
     
     [tzImagePickerVc showProgressHUD];
-    NSMutableArray *photos = [NSMutableArray array];
     NSMutableArray *assets = [NSMutableArray array];
-    NSMutableArray *infoArr = [NSMutableArray array];
+    NSMutableArray *photos;
+    NSMutableArray *infoArr;
+    if (tzImagePickerVc.onlyReturnAsset) { // not fetch image
+        for (NSInteger i = 0; i < tzImagePickerVc.selectedModels.count; i++) {
+            TZAssetModel *model = tzImagePickerVc.selectedModels[i];
+            [assets addObject:model.asset];
+        }
+    } else { // fetch image
+        photos = [NSMutableArray array];
+        infoArr = [NSMutableArray array];
         for (NSInteger i = 0; i < tzImagePickerVc.selectedModels.count; i++) { [photos addObject:@1];[assets addObject:@1];[infoArr addObject:@1]; }
         
         __block BOOL havenotShowAlert = YES;
@@ -390,6 +398,7 @@ static CGFloat itemMargin = 5;
                 }
             } networkAccessAllowed:YES];
         }
+    }
     if (tzImagePickerVc.selectedModels.count <= 0) {
         [self didGetAllPhotos:photos assets:assets infoArr:infoArr];
     }