fix: change image model to SDXL (FLUX access restricted)

app.py

@@ -17,7 +17,7 @@ from transformers import (
 )
 
 VL_MODEL_ID = "Qwen/Qwen2.5-VL-7B-Instruct"
-IMAGE_MODEL_ID = "black-forest-labs/FLUX.1-schnell"
+IMAGE_MODEL_ID = "stabilityai/stable-diffusion-xl-base-1.0"
 
 
 def _load_font():
@@ -322,11 +322,10 @@ def generate_cartoon_image(prompt: str) -> Image.Image:
 
         image = IMAGE_PIPELINE(
             prompt=enhanced_prompt,
-            num_inference_steps=4,
-            guidance_scale=0.0,
+            num_inference_steps=30,
+            guidance_scale=7.5,
             height=768,
             width=1024,
-            max_sequence_length=256,
         ).images[0]
         return image
     except Exception as e: