diff --git a/fftcg/carddb.py b/fftcg/carddb.py
index 30d7ab4..72c4103 100644
--- a/fftcg/carddb.py
+++ b/fftcg/carddb.py
@@ -1,7 +1,8 @@
 from __future__ import annotations
 
-import bz2
+import json
 import pickle
+import zipfile
 
 from .card import Card
 from .cards import Cards
@@ -15,6 +16,9 @@ class CardDB:
     __cards: dict[Code, Card]
     __face_to_url: dict[str, str]
 
+    __DB_FILE_NAME = "cards.pickle"
+    __MAPPING_FILE_NAME = "face_to_url.json"
+
     def __new__(cls) -> CardDB:
         if CardDB.__instance is None:
             CardDB.__instance = object.__new__(cls)
@@ -29,24 +33,48 @@ class CardDB:
     def __getitem__(self, code: Code) -> Card:
         return self.__cards[code]
 
-    def __pickle(self):
-        # pickle db file
-        with bz2.BZ2File(CARDDB_FILE_NAME, "w") as file:
-            pickle.dump(self.__cards, file)
-            pickle.dump(self.__face_to_url, file)
-
-    def update(self, cards: Cards):
-        for card in cards:
-            self.__cards[card.code] = card
-
-        self.__pickle()
-
     def get_face_url(self, face: str) -> str:
         if face in self.__face_to_url:
             return self.__face_to_url[face]
         else:
             return face
 
+    def __pickle(self) -> None:
+        with zipfile.ZipFile(CARDDB_FILE_NAME, "w", compression=zipfile.ZIP_LZMA) as zip_file:
+            # cards db
+            with zip_file.open(CardDB.__DB_FILE_NAME, "w") as file:
+                pickle.dump(self.__cards, file)
+
+            # face_to_url mapping
+            with zip_file.open(CardDB.__MAPPING_FILE_NAME, "w") as file:
+                file.write(json.dumps(self.__face_to_url, indent=2).encode("utf-8"))
+
+    def __unpickle(self) -> None:
+        # unpickle db file
+        self.__cards.clear()
+        self.__face_to_url.clear()
+        try:
+            with zipfile.ZipFile(CARDDB_FILE_NAME, "r") as zip_file:
+                # cards db
+                with zip_file.open(CardDB.__DB_FILE_NAME, "r") as file:
+                    self.__cards |= pickle.load(file)
+
+                # face_to_url mapping
+                with zip_file.open(CardDB.__MAPPING_FILE_NAME, "r") as file:
+                    self.__face_to_url |= json.load(file)
+
+        except FileNotFoundError:
+            pass
+
+    def load(self) -> None:
+        self.__unpickle()
+
+    def update(self, cards: Cards) -> None:
+        for card in cards:
+            self.__cards[card.code] = card
+
+        self.__pickle()
+
     def upload_prompt(self) -> None:
         faces = list(set([
             card[lang].face
@@ -63,17 +91,3 @@ class CardDB:
                     self.__face_to_url[face] = face_url
 
         self.__pickle()
-
-    def __unpickle(self):
-        # unpickle db file
-        self.__cards.clear()
-        self.__face_to_url.clear()
-        try:
-            with bz2.BZ2File(CARDDB_FILE_NAME, "r") as file:
-                self.__cards |= pickle.load(file)
-                self.__face_to_url |= pickle.load(file)
-        except FileNotFoundError:
-            pass
-
-    def load(self) -> None:
-        self.__unpickle()
diff --git a/fftcg/utils.py b/fftcg/utils.py
index c0a2ef6..bda6858 100644
--- a/fftcg/utils.py
+++ b/fftcg/utils.py
@@ -7,7 +7,7 @@ GRID = Grid((10, 7))  # default in TTsim: 10 columns, 7 rows
 RESOLUTION = Grid((429, 600))  # default in TTsim: 480x670 pixels per card
 DECKS_DIR_NAME = "decks"  # name of decks directory
 IMAGES_DIR_NAME = "images"  # name of images directory
-CARDDB_FILE_NAME = "carddb.pickle.bz2"  # name of card book file
+CARDDB_FILE_NAME = "carddb.zip"  # name of card db file
 # card back URL (image by Aurik)
 CARD_BACK_URL = "http://cloud-3.steamusercontent.com/ugc/948455238665576576/85063172B8C340602E8D6C783A457122F53F7843/"