diff --git a/ai_image_gen/ai_image_gen/backend/generation.py b/ai_image_gen/ai_image_gen/backend/generation.py
index dbcb393..f9067da 100644
--- a/ai_image_gen/ai_image_gen/backend/generation.py
+++ b/ai_image_gen/ai_image_gen/backend/generation.py
@@ -1,6 +1,7 @@
 import asyncio
 import datetime
 import os
+from collections.abc import Sequence
 from enum import Enum
 
 import reflex as rx
@@ -11,6 +12,14 @@
 
 DEFAULT_IMAGE = "/default.webp"
 API_TOKEN_ENV_VAR = "REPLICATE_API_TOKEN"
+MODEL_ENV_VAR = "REPLICATE_MODEL"
+UPSCALE_MODEL_ENV_VAR = "REPLICATE_UPSCALE_MODEL"
+
+DEFAULT_MODEL = "google/imagen-4-fast"
+# philz1337x /clarity-upscaler:029d48aa
+DEFAULT_UPSCALE_MODEL = (
+    "029d48aa21712d6769d7a46729c1edf0e4d41919c70b270785f10abb82989ba5"
+)
 
 CopyLocalState = rx._x.client_state(default=False, var_name="copying")
 
@@ -67,7 +76,7 @@ async def generate_image(self):
 
             # Await the output from the replicate API
             response = await replicate.predictions.async_create(
-                "5f24084160c9089501c1b3545d9be3c27883ae2239b6f412990e82d4a6210f8f",
+                os.environ.get(MODEL_ENV_VAR, DEFAULT_MODEL),
                 input=input,
             )
 
@@ -99,8 +108,12 @@ async def generate_image(self):
                 await asyncio.sleep(0.15)
             async with self:
                 self.upscaled_image = ""
-                self.output_image = response.output[0]
-                self.output_list = [] if len(response.output) == 1 else response.output
+                if isinstance(response.output, str):
+                    self.output_image = response.output
+                    self.output_list = []
+                elif isinstance(response.output, Sequence):
+                    self.output_image = response.output[0]
+                    self.output_list = list(response.output[1:])
                 self._reset_state()
 
         except Exception as e:
@@ -152,7 +165,7 @@ async def upscale_image(self):
 
             # Await the output from the replicate API
             response = await replicate.predictions.async_create(
-                "029d48aa21712d6769d7a46729c1edf0e4d41919c70b270785f10abb82989ba5",
+                os.environ.get(UPSCALE_MODEL_ENV_VAR, DEFAULT_UPSCALE_MODEL),
                 input=input,
             )