Use components and output path.

app.py

@@ -1,3 +1,4 @@
+import os
 import gradio as gr
 import random
 from random import randint
@@ -17,9 +18,13 @@ def inference(img):
     #INPUT_DIR = "/tmp/input_image" + str(_id) + "/"
     OUTPUT_DIR = "/tmp/output_image" + str(_id) + "/"
     img.save(OUTPUT_DIR + "1.jpg", "JPEG")
+    return os.path.join(OUTPUT_DIR, "1_out.jpg")
+
+input_image = gr.inputs.Image(type="pil", label="Input")
+output_image = gr.outputs.Image(type="file", label="Output")
 
 gr.Interface(
     inference,
-    [gr.inputs.Image(type="pil", label="Input")],
-    gr.outputs.Image(type="file", label="Output")
+    inputs=[input_image],
+    outputs=[output_image]
 ).launch()