Switch to SDXL Turbo model and fix parameters

app.py

@@ -8,8 +8,8 @@ from huggingface_hub import InferenceClient
 app = FastAPI(title="ImageGen API")
 
 # Choose a model that supports text->image via Inference API.
-# FLUX.1-schnell is fast; you can swap for SDXL or others later.
-MODEL_ID = os.getenv("MODEL_ID", "black-forest-labs/FLUX.1-schnell")
+# SDXL Turbo is fast; you can swap for other models later.
+MODEL_ID = os.getenv("MODEL_ID", "stabilityai/sdxl-turbo")
 HF_TOKEN = os.getenv("HF_TOKEN")  # set in Space Secrets
 client = InferenceClient(model=MODEL_ID, token=HF_TOKEN)
 
@@ -30,9 +30,10 @@ def generate(req: GenReq):
         # InferenceClient returns a PIL.Image for text_to_image
         img = client.text_to_image(
             prompt=req.prompt,
-            size=f"{req.width}x{req.height}",
+            width=req.width,
+            height=req.height,
             seed=req.seed,
-            num_inference_steps=req.num_inference_steps
+            num_inference_steps=req.num_inference_steps or 1  # SDXL Turbo works best with 1 step
         )
         buf = io.BytesIO()
         img.save(buf, format="PNG")