Supported formats and thumbnails
FreeImages, videos, RAW files, documents, and shell thumbnails.
FenSight decides support in two layers: known extensions enter the normal ingest pipeline, then preview generation chooses the fastest safe thumbnail path for that file. Images and videos become visual board items, documents and creative project files become document/reference items, .fns files become board-preview items, and optional generic import can add other non-hidden files through Windows Shell thumbnails or file icons.
Screenshot coming soon
FenSight board showing mixed image, RAW, video, document, and project-file thumbnails
Where formats enter the app
File -> Import Folder...
Recursively imports supported images, videos, documents, asset references, board previews, and image sequences.
Explorer -> drag files or folders onto the canvas
Mixed drops use the same extension groups. With Accept all file types on, remaining non-hidden files become generic document items.
Settings -> Import -> Accept all file types on drop (uses Shell thumbnail / file icon)
Enables the generic fallback for file types outside the normal pipeline. Toggling it off leaves existing generic items on the board.
Settings -> Import -> Visualize audio files (waveform display)
When Accept all file types is also on, supported audio files can import as waveform AudioItem objects instead of generic icons.
File -> Pre-render previews...
Builds PreviewCache entries ahead of import for preview-supported image formats such as PNG, JPEG, TIFF, WebP, JXL, AVIF, HDR, DNG, HEIC, and HEIF.
File -> Rebuild Thumbnails
Regenerates missing board previews. Video thumbnails run through the dedicated video backfill path first, then still-missing image/sequence/document thumbnails are rebuilt.
Video item -> Generate Video Thumbnail
Forces representative-frame regeneration for the selected video item or items.
Canonical extension groups
These groups come from the app's import pipeline. They determine which files are imported directly before the optional generic Shell-thumbnail fallback is considered.
Thumbnail source order
The visible thumbnail is not always decoded by the same library. FenSight picks a source based on the file type, board-load mode, cache state, and whether the work is a bulk operation.
Settings that affect thumbnails
Bulk thumbnail safety
FenSight intentionally avoids Shell thumbnail generation in large batch paths. Third-party Windows shell extensions can hook every Shell thumbnail request, and sustained high-volume calls are a reliability risk. Bulk preview generation therefore prefers direct decode, ImageSharp, and Magick.NET with skipShellFallback set, while Shell content thumbnails remain available for bounded on-demand cases.
- AI/index preview generation uses direct decode/Magick.NET first and can skip Shell fallback in bulk mode.
- Video thumbnail loops bypass Shell icon fallback and use cache-only Shell reads plus WPF MediaPlayer/LibVLC frame generation.
- Individual user-triggered previews and generic file drops may still use Shell thumbnails because the request count is bounded by the action.
When a thumbnail is missing
A missing thumbnail does not always mean the file failed to import. Some formats are accepted as proxy items first, some video thumbnails arrive after Phase 4 backfill, and generic files depend on the Windows thumbnail provider installed for that file type.
- If a video shows a placeholder, use the item context menu's Generate Video Thumbnail command or File -> Rebuild Thumbnails.
- If a document or project file shows an icon, Windows may not have a content thumbnail or Preview Pane handler for that extension.
- If a RAW/HDR/texture file opens as a placeholder during a large import, the background preview and LOD backfill paths may still replace it later.
- If Accept all file types is off, unsupported files are skipped rather than imported as generic icon items.
Supported formats, thumbnail caching, rebuild thumbnails, Shell-thumbnail fallback, and audio waveform import are Free. Paid tiers are not required for the format and thumbnail pipeline itself.
A file type can be accepted without guaranteeing a rich visual preview on every machine. Shell and Preview Pane thumbnails depend on installed Windows codecs, shell extensions, or application preview handlers.
Connected guides
Follow these related pages when the workflow crosses into setup, search, organization, export, security, or another board-level system.