diff --git a/file.py b/file.py
index ea1f218..ef3eff1 100644
--- a/file.py
+++ b/file.py
@@ -67,14 +67,20 @@ def raedZip(bookid: str, index: int):
         return str(e), ""
 
 
-def thumbnail(input, minSize: int = 600):
+def thumbnail(input, minSize: int = 600, encode:str="webp"):
     img = cv2.imdecode(np.frombuffer(input, np.uint8), cv2.IMREAD_COLOR)
     height = img.shape[0]  # 图片高度
     width = img.shape[1]  # 图片宽度
-    if height > width:
-        newshape = (minSize, int(minSize / width * height))
+    if minSize < np.amin((height,width)):
+        if height > width:
+            newshape = (minSize, int(minSize / width * height))
+        else:
+            newshape = (int(minSize / height * width), minSize)
+        img = cv2.resize(img, newshape)
+    if encode == "webp":
+        success, encoded_image = cv2.imencode(".webp", img, [cv2.IMWRITE_WEBP_QUALITY, 75])
+    elif encode == "jpg":
+        success, encoded_image = cv2.imencode(".jpg", img, [cv2.IMWRITE_JPEG_QUALITY, 75])
     else:
-        newshape = (int(minSize / height * width), minSize)
-    img = cv2.resize(img, newshape)
-    success, encoded_image = cv2.imencode(".webp", img, [cv2.IMWRITE_WEBP_QUALITY, 75])
+        return input
     return encoded_image.tobytes()
diff --git a/web/api_Img.py b/web/api_Img.py
index 4830b0e..03db755 100644
--- a/web/api_Img.py
+++ b/web/api_Img.py
@@ -16,9 +16,9 @@ def img(bookid, index):  # 图片接口
     if isinstance(data, str):
         abort(404)
     if request.args.get("mini") == "yes":
-        data = file.thumbnail(data)
+        data = file.thumbnail(data,encode="jpg")
     else:
-        data = file.thumbnail(data,2400)
+        data = file.thumbnail(data,1500,)
     response = make_response(data)  # 读取文件
     del data
     response.headers.set("Content-Type", "image/Webp")