fix(upscaler): use gr.File() output so API receives single path string

- FnNode output changed from gr.Image to gr.File to avoid list serialization
- image_to_filepath now handles dict and list-of-dict formats from Gradio

Co-authored-by: Cursor <cursoragent@cursor.com>

app.py

@@ -18,24 +18,30 @@ bg_remover = GradioNode(
 
 
 def image_to_filepath(image):
-    """Convert image input (list or path) to a single filepath string.
-    Phips/Upscaler API expects 'filepath', but upstream nodes (e.g. INPUT Image) may pass a list."""
+    """Convert image input (list, dict, or path) to a single filepath string.
+    Phips/Upscaler API expects 'filepath', but upstream nodes may pass a list or dict."""
     if image is None:
         return None
     if isinstance(image, str):
         return image
+    if isinstance(image, dict) and "path" in image and isinstance(image["path"], str):
+        return image["path"]
     if isinstance(image, (list, tuple)) and len(image) > 0:
         first = image[0]
-        return first if isinstance(first, str) else None
+        if isinstance(first, str):
+            return first
+        if isinstance(first, dict) and "path" in first and isinstance(first["path"], str):
+            return first["path"]
     return None
 
 
 # Helper node: normalizes image (list/path) → single filepath for APIs that require it (e.g. Phips/Upscaler)
+# Use gr.File() so the value is passed as a single path string; gr.Image() can serialize as list and Upscaler expects filepath.
 image_to_path = FnNode(
     image_to_filepath,
     name="Image to path (for Upscaler)",
     inputs={"image": gr.Image(label="Input Image")},
-    outputs={"image": gr.Image(label="Image (filepath)", type="filepath")},
+    outputs={"image": gr.File(label="Image path")},
 )
 
 # 2. Image Upscaler
@@ -45,7 +51,7 @@ upscaler = GradioNode(
     api_name="/upscale_image",
     run_locally=False,
     inputs={
-        "image": image_to_path.image,
+        "image": image_to_path.image,  # single path from File output
     },
     outputs={
         "upscaled_image": gr.Image(label="Upscaled Image"),