Fix darkened texture: lower alpha threshold from 0.5 to 0.05

app.py

@@ -377,7 +377,7 @@ def preprocess_image(input: Image.Image) -> Image.Image:
     output = output.crop(bbox)  # type: ignore
     output_np = np.array(output)
     alpha = output_np[:, :, 3]
-    output_np[:, :, :3][alpha < 0.5 * 255] = [0, 0, 0]
+    output_np[:, :, :3][alpha < 0.05 * 255] = [0, 0, 0]
     output = Image.fromarray(output_np[:, :, :3])
     return output