diff --git a/server/szurubooru/func/images.py b/server/szurubooru/func/images.py
index e28520dd..7daf46ff 100644
--- a/server/szurubooru/func/images.py
+++ b/server/szurubooru/func/images.py
@@ -41,7 +41,7 @@ class Image:
     def frames(self) -> int:
         return self.info["streams"][0]["nb_read_frames"]
 
-    def resize_fill(self, width: int, height: int) -> None:
+    def resize_fill(self, width: int, height: int, pixel_format: str = "rgb32") -> None:
         width_greater = self.width > self.height
         width, height = (-1, height) if width_greater else (width, -1)
 
@@ -51,7 +51,7 @@ class Image:
             "-f",
             "image2",
             "-filter:v",
-            "scale='{width}:{height}'".format(width=width, height=height),
+            "format={pixel_format},scale={width}:{height}:flags=bicubic".format(pixel_format=pixel_format, width=width, height=height),
             "-map",
             "0:v:0",
             "-vframes",
diff --git a/server/szurubooru/func/posts.py b/server/szurubooru/func/posts.py
index be2259cf..e165fd03 100644
--- a/server/szurubooru/func/posts.py
+++ b/server/szurubooru/func/posts.py
@@ -689,6 +689,7 @@ def generate_post_thumbnail(post: model.Post) -> None:
         image.resize_fill(
             int(config.config["thumbnails"]["post_width"]),
             int(config.config["thumbnails"]["post_height"]),
+            "rgb24",
         )
         files.save(get_post_thumbnail_path(post), image.to_jpeg())
     except errors.ProcessingError: