diff --git a/nanodet/data/dataset/yolo.py b/nanodet/data/dataset/yolo.py
index 6c5efff40..f6b75b986 100644
--- a/nanodet/data/dataset/yolo.py
+++ b/nanodet/data/dataset/yolo.py
@@ -18,8 +18,8 @@
 from collections import defaultdict
 from typing import Optional, Sequence
 
-import cv2
 import numpy as np
+from imagesize import imagesize
 from pycocotools.coco import COCO
 
 from .coco import CocoDataset
@@ -92,8 +92,7 @@ def yolo_to_coco(self, ann_path):
             with open(ann_file, "r") as f:
                 lines = f.readlines()
 
-            image = cv2.imread(image_file)
-            height, width = image.shape[:2]
+            width, height = imagesize.get(image_file)
 
             file_name = os.path.basename(image_file)
             info = {
diff --git a/nanodet/model/arch/one_stage_detector.py b/nanodet/model/arch/one_stage_detector.py
index 90aa3f6f3..8a0f61a81 100644
--- a/nanodet/model/arch/one_stage_detector.py
+++ b/nanodet/model/arch/one_stage_detector.py
@@ -60,7 +60,7 @@ def inference(self, meta):
             time2 = time.time()
             print("forward time: {:.3f}s".format((time2 - time1)), end=" | ")
             results = self.head.post_process(preds, meta)
-            
+
             if is_cuda_available:
                 torch.cuda.synchronize()
 
diff --git a/requirements.txt b/requirements.txt
index 4f88e6515..d1a281b11 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,5 @@
 Cython
+imagesize
 matplotlib
 numpy
 omegaconf>=2.0.1