Documentation · How-to

Folder Sync

Point Numonic at any folder on your computer and new AI-generated images are imported automatically with full metadata extraction. Six steps below to set it up, plus troubleshooting and FAQ.

You will learn how to: connect a folder · grant permission · review the Import Preview · install Numonic as a PWA · fix common reconnection issues.

Setup — six concrete steps

You can complete every step below in under five minutes on a supported browser (Chrome 86+ or Edge 86+ on desktop). Steps 5 and 6 happen automatically once the folder is connected.

  1. 1

    Sign in to Numonic

    Folder Sync runs inside your Numonic library — first create a free account or sign in to an existing one. Folder Sync is available on all tiers, including free.

  2. 2

    Open the Import page

    Once signed in, open the Import page from the left sidebar (or visit /app/import directly). This is the hub for all asset ingestion.

  3. 3

    Click "Connect Your First Folder"

    Click the Connect Your First Folder button. Your browser will open a folder picker — choose any local directory you want Numonic to watch (your ComfyUI output folder, your Midjourney Downloads folder, a Stable Diffusion outputs folder, or any creative workspace).

  4. 4

    Grant read permission

    Your browser will ask permission to read the folder. Click View files (Chrome / Edge) to grant access. Numonic only reads — your local files are never modified, moved, or deleted.

  5. 5

    Review the Import Preview

    If the folder already contains files, an Import Preview appears automatically. Numonic detects what tools generated the assets (ComfyUI, Midjourney, Stable Diffusion, Generic) and lets you choose what to import. Click Import All or pick a subset.

  6. 6

    Leave the tab open — sync runs automatically

    From now on, any new files saved to the folder are detected and uploaded automatically with full metadata extraction. Folder Sync runs while Numonic is open in a browser tab; close the tab and sync pauses until you reopen it. Supported formats: PNG, JPG, WebP, GIF, MP4, WebM, MOV, and ZIP archives.

Recommended folders by tool

ComfyUI
Your output folder (default: ComfyUI/output)
Midjourney
Your Downloads folder, or wherever you save Midjourney images
Stable Diffusion (A1111)
Your outputs folder (default: stable-diffusion-webui/outputs)
Flux / DALL-E / Other
Any folder where you save generated images

Smart Import — what happens automatically

Once a folder is connected (steps 1–6 above), Numonic applies the following automatically to every file that arrives. To disable per-tool detection for faster bulk imports, toggle off Smart Import in the folder's settings on the Import page.

Source detection

Images are tagged automatically as ComfyUI, Midjourney, Stable Diffusion, or Generic based on embedded metadata.

Folder → collection

Subfolders in the watched folder become collections in Numonic, preserving your organisation.

ZIP extraction

Drop a ZIP (e.g., Midjourney "Download All") and Numonic extracts, source-detects, and imports each image individually. Up to 1.1 GB per ZIP.

Smart deduplication

Already-imported files are skipped automatically. The watcher tracks seen files via IndexedDB and remembers across sessions.

Browser support — what to use

Folder Sync uses the File System Access API. Detection latency depends on browser version.

Chrome 129+ / Edge 129+

Real-time detection via FileSystemObserver API. New images are uploaded within seconds of being saved.

Chrome 86–128 / Edge 86–128

Periodic polling every 5 seconds. Reliable but slightly delayed compared to real-time detection.

Firefox / Safari

Not supported — File System Access API is not implemented. Use Chrome or Edge for folder watching; manual upload still works.

DevContainer / Codespaces users: The embedded browser windows inside VS Code or GitHub Codespaces do not support the File System Access API. Open Numonic in a real desktop browser window.

Install as app (PWA) — recommended

Installing Numonic as a Progressive Web App gives you a dedicated window, quick launch from dock/Start menu, and (on Chrome 122+) better folder-permission persistence between sessions.

Chrome

  1. Look for the install icon (⊕) in the address bar, OR
  2. Open the menu (⋮) → Install Numonic AI…
  3. Click Install in the dialog

To uninstall: visit chrome://apps, right-click Numonic → Remove.

Edge

  1. Open the menu (…)
  2. Select Apps → Install this site as an app
  3. Confirm the installation

To uninstall: visit edge://apps, right-click Numonic → Uninstall.

Troubleshooting

Common issues with concrete fixes. Each entry explains why it happens and exactly what to click.

Folder shows "Needs Reconnection"

Why it happens: Browser file system permissions are revoked when you close the browser. They don't persist across sessions for security reasons.

Solution: Click the Reconnect button next to the folder on the Import page. Your browser will ask for permission again — grant it, and watching resumes immediately.

"Can't open this folder because it contains system files"

Why it happens: Chromium-based browsers (Chrome, Edge, Brave) block web apps from accessing certain top-level folders to protect your system. Blocked locations include Desktop, Downloads, Documents (top-level), your home directory (~), Applications, Library (Mac), AppData, and Program Files (Windows).

Solution: Select a subfolder inside these locations instead. For example, choose Downloads/midjourney-images instead of Downloads, or create a dedicated folder like ComfyUI-Output and select that. This restriction is a browser security feature and cannot be bypassed.

Files not being detected

Why it happens: Supported file types are PNG, JPG, WebP, GIF, MP4, WebM, MOV, and ZIP. Other types are ignored.

Solution:
  • Confirm the file is a supported format
  • Check the folder is showing the Watching status on the Import page
  • On Chrome 86–128, wait up to 5 seconds for the next poll
  • Pause and resume the watcher to force a fresh scan

Resume button doesn't work after switching browsers

Why it happens: Folder configurations are shared between Chromium-based browsers (Chrome/Edge/Brave share storage), but file access permissions are browser-specific and can't be transferred for security reasons.

Solution: Click Resume once — it will detect the permission gap and show a Reconnect button. Click Reconnect to grant permission in the current browser. Alternatively, return to the original browser, or remove the folder and re-add it in the new browser.

"Browser not supported" message

Why it happens: You're using a browser that doesn't support the File System Access API (Firefox, Safari, or any mobile browser).

Solution: Switch to Chrome 86+ or Edge 86+ on desktop. Note: DevContainer / GitHub Codespaces embedded browser windows also do not support the API — open Numonic in a real desktop browser window.

FAQ

Questions we get most often from prospects evaluating Folder Sync before signing up.

Basic usage

Can I watch multiple folders at once?
Yes. Connect as many folders as you like — each is watched independently. Useful if different AI tools save to different locations.
Does it watch subfolders?
Yes. All subfolders inside the connected folder are watched, and subfolder structure is preserved as collections in Numonic.
How do I stop watching a folder?
Two options. Pause temporarily stops watching but keeps the folder connected and remembered. Remove fully disconnects. Paused folders resume without re-granting permission.

ZIP files

How do ZIP files work?
When you save a ZIP to a watched folder, Numonic automatically extracts the supported media files inside (PNG, JPG, WebP, GIF, MP4, WebM, MOV) and imports each one individually. Folder structure inside the ZIP becomes collections.
Do Midjourney batch downloads work?
Yes. Midjourney "Download All" ZIPs are fully supported — each image is extracted, source-detected as Midjourney, and any folder structure is preserved.
Is there a size limit?
ZIP files up to 1.1 GB are supported. Extraction happens in your browser, so very large ZIPs may take a moment.

Browser & permissions

Does sync run when my browser is closed?
No. Folder Sync only runs while Numonic is open in a browser tab. Install Numonic as a PWA (instructions below) for a near-native experience that launches from your dock.
Why do I need to grant permission again after closing the browser?
Browsers don't persist File System Access API permissions across sessions for security. Click Reconnect when you return — it's a one-click step.
What happens if a file is too large?
Individual files over 100 MB are skipped. Most AI-generated images are well under this. For larger files, use manual drag-and-drop upload.

Ready to set up Folder Sync?

Create a free Numonic account, open the Import page, and connect your first folder. The full six-step setup above takes under five minutes.

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