fix bbox when resizing large vertical images

src/app.py

@@ -127,10 +127,10 @@ def _process(
 ) -> tuple[tuple[Image.Image, Image.Image], gr.DownloadButton]:
     # enforce max dimensions for pymatting performance reasons
     if img.width > 2048 or img.height > 2048:
-        orig_width = img.width
+        orig_res = max(img.width, img.height)
         img.thumbnail((2048, 2048))
         if isinstance(prompt, tuple):
-            x0, y0, x1, y1 = (int(x * 2048 / orig_width) for x in prompt)
+            x0, y0, x1, y1 = (int(x * 2048 / orig_res) for x in prompt)
             prompt = (x0, y0, x1, y1)
 
     mask, bbox, time_log = _gpu_process(img, prompt)