> ## Documentation Index > Fetch the complete documentation index at: https://docs.comfy.org/llms.txt > Use this file to discover all available pages before exploring further. # Stability Stable Image Ultra - ComfyUI Native Node Documentation > A node that generates high-quality images using Stability AI's ultra stable diffusion model ComfyUI Native Stability Stable Image Ultra Node The Stability Stable Image Ultra node uses Stability AI's Stable Diffusion Ultra API to generate high-quality images. It supports both text-to-image and image-to-image generation, creating detailed and artistic visuals from text prompts. ## Parameters ### Required Parameters | Parameter | Type | Default | Description | | ------------- | ------- | ------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | prompt | string | "" | Text description of what you want to generate. Better results come from clear, descriptive prompts that specify elements, colors and themes. You can control word importance using `(word:weight)` format, where weight is 0-1. For example: `The sky was (blue:0.3) and (green:0.8)` makes the sky more green than blue. | | aspect\_ratio | select | "1:1" | Width to height ratio of output image | | style\_preset | select | "None" | Optional preset style for generated image | | seed | integer | 0 | Random seed for noise generation (0-4294967294) | ### Optional Parameters | Parameter | Type | Default | Description | | ---------------- | ------ | ------- | ---------------------------------------------------------------------------------------------------------------- | | image | image | - | Input image for image-to-image generation | | negative\_prompt | string | "" | Describes what you don't want in the output image. This is an advanced feature | | image\_denoise | float | 0.5 | Denoising strength for input image (0.0-1.0). 0.0 keeps input image unchanged, 1.0 is like having no input image | ### Output | Output | Type | Description | | ------ | ----- | --------------- | | IMAGE | image | Generated image | ## Notes * image\_denoise has no effect when no input image is provided * No preset style is applied when style\_preset is "None" * For image-to-image, input images are converted to the proper format before API submission ## Source Code \[Node source code (Updated on 2025-05-03)] ```python theme={null} class StabilityStableImageUltraNode: """ Generates images synchronously based on prompt and resolution. """ RETURN_TYPES = (IO.IMAGE,) DESCRIPTION = cleandoc(__doc__ or "") # Handle potential None value FUNCTION = "api_call" API_NODE = True CATEGORY = "api node/image/stability" @classmethod def INPUT_TYPES(s): return { "required": { "prompt": ( IO.STRING, { "multiline": True, "default": "", "tooltip": "What you wish to see in the output image. A strong, descriptive prompt that clearly defines" + "What you wish to see in the output image. A strong, descriptive prompt that clearly defines" + "elements, colors, and subjects will lead to better results. " + "To control the weight of a given word use the format `(word:weight)`," + "where `word` is the word you'd like to control the weight of and `weight`" + "is a value between 0 and 1. For example: `The sky was a crisp (blue:0.3) and (green:0.8)`" + "would convey a sky that was blue and green, but more green than blue." }, ), "aspect_ratio": ([x.value for x in StabilityAspectRatio], { "default": StabilityAspectRatio.ratio_1_1, "tooltip": "Aspect ratio of generated image.", }, ), "style_preset": (get_stability_style_presets(), { "tooltip": "Optional desired style of generated image.", }, ), "seed": ( IO.INT, { "default": 0, "min": 0, "max": 4294967294, "control_after_generate": True, "tooltip": "The random seed used for creating the noise.", }, ), }, "optional": { "image": (IO.IMAGE,), "negative_prompt": ( IO.STRING, { "default": "", "forceInput": True, "tooltip": "A blurb of text describing what you do not wish to see in the output image. This is an advanced feature." }, ), "image_denoise": ( IO.FLOAT, { "default": 0.5, "min": 0.0, "max": 1.0, "step": 0.01, "tooltip": "Denoise of input image; 0.0 yields image identical to input, 1.0 is as if no image was provided at all.", }, ), }, "hidden": { "auth_token": "AUTH_TOKEN_COMFY_ORG", }, } def api_call(self, prompt: str, aspect_ratio: str, style_preset: str, seed: int, negative_prompt: str=None, image: torch.Tensor = None, image_denoise: float=None, auth_token=None): # prepare image binary if image present image_binary = None if image is not None: image_binary = tensor_to_bytesio(image, 1504 * 1504).read() else: image_denoise = None if not negative_prompt: negative_prompt = None if style_preset == "None": style_preset = None files = { "image": image_binary } operation = SynchronousOperation( endpoint=ApiEndpoint( path="/proxy/stability/v2beta/stable-image/generate/ultra", method=HttpMethod.POST, request_model=StabilityStableUltraRequest, response_model=StabilityStableUltraResponse, ), request=StabilityStableUltraRequest( prompt=prompt, negative_prompt=negative_prompt, aspect_ratio=aspect_ratio, seed=seed, strength=image_denoise, style_preset=style_preset, ), files=files, content_type="multipart/form-data", auth_token=auth_token, ) response_api = operation.execute() if response_api.finish_reason != "SUCCESS": raise Exception(f"Stable Image Ultra generation failed: {response_api.finish_reason}.") image_data = base64.b64decode(response_api.image) returned_image = bytesio_to_image_tensor(BytesIO(image_data)) return (returned_image,) ```