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File Preview

Preview images, text, PDFs, audio, and video files directly in Stackpane without downloading.

Overview

Stackpane provides inline file preview for common file types directly in the inspector panel. This lets you visually verify uploaded content without downloading files first.

Supported Formats

Images

Image files are rendered as resizable images with dimension display (width x height). Supported formats include JPEG, PNG, GIF, WebP, SVG, and other standard web image formats.

Text and JSON

Text files and JSON data are displayed in a monospaced, scrollable text view. The first 10,000 characters are shown for large files. JSON files are automatically pretty-printed for readability.

PDF

PDF files are rendered inline with continuous scrolling. You can scroll through pages directly in the inspector panel.

Audio and Video

Audio and video files are played using native macOS playback controls. You get standard play/pause, seek, and volume controls inline in the inspector.

Auto-Preview

Files under 5 MB are automatically previewed when you select them in the file browser. This threshold balances responsiveness with bandwidth usage.

For files larger than 5 MB, the inspector shows the file metadata (name, size, type) but does not load the preview automatically. Click the Preview button to manually load the preview for larger files.

File Metadata

The inspector always shows file metadata regardless of preview availability:

  • File name and full storage path
  • File size formatted as B, KB, or MB
  • Content type with a fallback to file extension inference when the MIME type is not set
  • Last updated timestamp
  • Custom metadata — editable key-value pairs that you can use for application-specific data

Editing Custom Metadata

  1. Click Edit in the metadata section.
  2. Add, modify, or remove key-value pairs.
  3. Click Save to persist the metadata changes to Cloud Storage.

Tips

  • Use the file browser to quickly verify that uploaded images have the correct dimensions and content
  • Preview JSON configuration files to check their structure without downloading
  • Custom metadata is useful for storing application context like uploadedBy, category, or version