diff --git a/app/logic/image_processing.py b/app/logic/image_processing.py
index ab15edd..f0c2819 100644
--- a/app/logic/image_processing.py
+++ b/app/logic/image_processing.py
@@ -194,7 +194,9 @@ class ImageProcessingMixin:
             return
         width, height = self.orig_img.size
         max_w, max_h = PREVIEW_MAX_SIZE
-        scale = min(max_w / width, max_h / height, 1.0)
+        scale = min(max_w / width, max_h / height)
+        if scale <= 0:
+            scale = 1.0
         size = (max(1, int(width * scale)), max(1, int(height * scale)))
         self.preview_img = self.orig_img.resize(size, Image.LANCZOS)
         self.preview_tk = ImageTk.PhotoImage(self.preview_img)