> ## Documentation Index
> Fetch the complete documentation index at: https://dripart-feat-openapi-i18n.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# MaskPreview - ComfyUI Built-in Node Documentation

> Complete documentation for the MaskPreview node in ComfyUI. Learn its inputs, outputs, parameters and usage.

The MaskPreview node saves mask data as a preview image to your ComfyUI output directory, allowing you to visually inspect mask data during workflow execution. It converts the input mask into a format suitable for image display and saves it with a configurable filename prefix.

## Inputs

| Parameter         | Description                                                      | Data Type      | Required | Range |
| ----------------- | ---------------------------------------------------------------- | -------------- | -------- | ----- |
| `mask`            | The mask data to be previewed and saved as an image              | MASK           | Yes      | -     |
| `filename_prefix` | Prefix for the output filename (default: "ComfyUI")              | STRING         | No       | -     |
| `prompt`          | Prompt information for metadata (automatically provided)         | PROMPT         | No       | -     |
| `extra_pnginfo`   | Additional PNG information for metadata (automatically provided) | EXTRA\_PNGINFO | No       | -     |

## Outputs

| Output Name | Description                                                               | Data Type |
| ----------- | ------------------------------------------------------------------------- | --------- |
| `ui`        | Contains the preview image information and metadata for display in the UI | DICT      |

> This documentation was AI-generated. If you find any errors or have suggestions for improvement, please feel free to contribute! [Edit on GitHub](https://github.com/Comfy-Org/embedded-docs/blob/main/comfyui_embedded_docs/docs/MaskPreview/en.md)

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