Extensions/ComfyUI-PreviewPlus
ComfyUI Extension

ComfyUI-PreviewPlus

Image preview and manual or automatic saving with generation metadata and optional workflow.

By dar06051990-oss·Created a day ago·Updated a day ago· 1
dar06051990-oss/ComfyUI-PreviewPlus
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ComfyUI-PreviewPlus

PreviewPlus is a compact image preview and saving node for ComfyUI. Save PNG, JPEG, or WebP images manually or automatically, with readable generation parameters and optional embedded workflow data.

Features

  • Three image formats: PNG and lossless WebP; JPEG with quality 100 and 4:4:4 subsampling (JPEG remains a lossy format).
  • Manual save: preview the result and click the diskette icon to download the image through the browser. Nothing is permanently written to output by manual downloads.
  • Auto Save: switch on to save generated images automatically; the diskette becomes a folder icon for selecting the destination.
  • Easy folder picker: quick access to Desktop, Downloads, Documents, Pictures and Home; navigate other drives or enter a full path. Default output resets the destination to ComfyUI's regular output folder.
  • Persistent global settings: Auto Save and its destination survive browser/server restarts, apply across workflows, and are shared by all PreviewPlus nodes in the same ComfyUI installation.
  • Workflow metadata: choose Parameters only or Full workflow. Full workflow enables restoring the original graph when re-importing a supported image.
  • Useful metadata: best-effort extraction of prompts, negative prompts, seed, steps, sampler, scheduler, CFG, denoise, checkpoint and size. Includes prompts from ComfyUI-PromptLora.
  • Compatibility: readable generation parameters in Forge Neo PNG Info and PixMeta; a JPEG drag-and-drop importer for embedded ComfyUI workflows.

Installation

  1. Go to the custom_nodes folder of your ComfyUI installation.

  2. Clone this repository:

    git clone https://github.com/dar06051990-oss/ComfyUI-PreviewPlus.git

    Alternatively, download the repository as ZIP from GitHub and extract the ComfyUI-PreviewPlus folder into ComfyUI/custom_nodes/.

  3. Restart ComfyUI and refresh the browser (Ctrl+F5 if needed).

  4. Add the node PreviewPlus from image / Preview Plus, then connect its images input to your generated image output.

No separate pip install is normally needed; the node uses ComfyUI's existing Python environment (including Pillow and NumPy).

Controls

| Control | Behavior | | --- | --- | | format | PNG, JPG, or WEBP | | workflow_json | Parameters only: no original workflow saved. Full workflow: original graph embedded. | | Auto Save | OFF by default; when ON, saves images immediately after node execution. | | Diskette icon | Download manually (visible only with Auto Save OFF). | | Folder icon | Choose the automatic save directory (visible only with Auto Save ON). |

When Auto Save is enabled, the destination defaults to the current ComfyUI output folder, not a hard-coded installation path. A different destination can be selected in the folder picker. The directory must already exist and be writable by ComfyUI.

Settings are kept at <ComfyUI user directory>/preview_plus/settings.json rather than in the extension folder. These settings are global to the installation; a second ComfyUI installation has its own settings.

Saving and restoring metadata

| Format | Parameters only | Full workflow | | --- | --- | --- | | PNG | Readable generation parameters; no original graph | Parameters and original ComfyUI workflow | | JPG | Readable EXIF generation parameters; no original graph | Parameters and workflow (via bundled JPEG importer) | | WebP | Readable EXIF generation parameters; no original graph | Parameters and workflow in ComfyUI-compatible EXIF fields |

Important: Parameters only means that the original ComfyUI graph is not embedded. Some tools may reconstruct a generic workflow from plain-text settings; that is not the original graph.

The node embeds information collected from the execution graph. Model-specific parameters, custom sampler implementations and some unusual prompt structures may not be fully represented in the human-readable fields. Full workflow data is the more complete record where supported.

Notes

  • The image preview uses ComfyUI's temporary directory. Auto Save OFF does not create permanent output files from this node.
  • JPEG metadata has an EXIF size limit. If a very large workflow cannot be stored in JPEG or WebP EXIF, use PNG or select Parameters only.
  • WebP is lossless here; JPEG is encoded at high quality but remains lossy.
  • Some Forge Neo versions may print non-fatal EXIF warnings while still displaying metadata.
  • Folder selection refers to the machine running ComfyUI, not necessarily the web browser's machine. Only use the folder-picker/settings endpoints on ComfyUI installations you trust; do not expose the server directly to the public internet.

Tested

The PNG/JPG/WebP formats, workflow switch, auto/manual save, and ComfyUI-PromptLora integration were tested on Windows with ComfyUI by the project author. Behavior can vary between ComfyUI versions and frontends.

Credits

The JPEG workflow import approach was informed by Amarillys/ComfyUI-JPG-Metadata (MIT). Thanks to its author for demonstrating JPEG workflow restoration in ComfyUI.

License

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