diff --git a/openlibrary/plugins/upstream/covers.py b/openlibrary/plugins/upstream/covers.py
index 68642f77671..c0d53c776e6 100644
--- a/openlibrary/plugins/upstream/covers.py
+++ b/openlibrary/plugins/upstream/covers.py
@@ -25,11 +25,16 @@ def setup():
     pass
 
 
-class image_validator:
+class ImageValidator:
     def __init__(self):
         self.max_file_size = 10 * 1024 * 1024  # 10 MB
         self.allowed_extensions = {'.jpg', '.jpeg', '.gif', '.png'}
 
+    def validate(self, file):
+        self.validate_extension(file.filename)
+        self.validate_size(file.file)
+        self.validate_image(file.file)
+
     def validate_size(self, file_data):
         file_size = len(file_data.read())
         file_data.seek(0)
@@ -72,7 +77,10 @@ def POST(self, key):
         # remove references to field storage objects
         web.ctx.pop("_fieldstorage", None)
 
-        data = self.upload(key, i)
+        try:
+            data = self.upload(key, i)
+        except ValueError as e:
+            return render_template("covers/add", book, status=web.storage({"code": 1}))
 
         if coverid := data.get('id'):
             if isinstance(i.url, bytes):
@@ -88,18 +96,10 @@ def upload(self, key, i):
         olid = key.split("/")[-1]
 
         if i.file is not None and hasattr(i.file, 'file'):
-            file_data = i.file.file
-            filename = i.file.filename
-
-            validator = image_validator()
-            try:
-                validator.validate_extension(filename)
-                validator.validate_size(file_data)
-                validator.validate_image(file_data)
-            except ValueError as e:
-                return web.storage({'error': str(e)})
-
-            data = file_data
+            validator = ImageValidator()
+            validator.validate(i.file)
+
+            data = i.file.file
         else:
             data = None