Supported file formats (view)
HEIC/HEIF, JPEG, JFIF, PNG, WebP, GIF, AVIF, SVG, BMP, TIFF, MP4, WebM, MOV, WMV, PDF, and ICO
About WMV
No browser can decode WMV, so ffmpeg.wasm is loaded from a CDN and does the decoding — entirely inside your browser, with nothing uploaded. Gallery thumbnails are made by extracting a single frame, and opening one in the lightbox shows a "Convert and play" button: pressing it converts the whole video to MP4 and plays the result. The converter is about 31MB and is fetched the first time a WMV needs it; converting a whole video takes roughly as long as the video itself, with a progress bar and a cancel button. Converted videos are kept for the rest of the session, so reopening one plays it right away. Slideshow, hover playback, and the conversion features do not cover WMV.
Convertible file formats
Images
HEIC/HEIF, JPEG, PNG, WebP, BMP, TIFF, AVIF → WebP, PNG, JPEG, or PDF (one file at a time, or in bulk). "High compression" WebP/JPEG use a much lower quality setting for a substantially smaller file size. Lossy formats (WebP/JPEG) are marked with ▸ in the lightbox format menu: choose "Preview" from the submenu to overlay the original and the converted result with a divider, showing both file sizes, before you download.
Video
MP4, WebM, and MOV → Sound, Thumbnail, or Rotate. Sound extracts the audio track as-is (no re-encoding), so the resulting file's actual codec depends on the source (e.g. AAC, Opus); files with no audio track are skipped in bulk, or shown an error individually. Thumbnail saves a JPEG snapshot from early in the video (bulk downloads one per video). Rotate (lightbox only) saves a copy rotated 90° clockwise, 180°, or 90° counter-clockwise by rewriting the container's rotation metadata — the video itself isn't re-encoded, so it finishes almost instantly.
PDF
A PDF opened in the lightbox can be split into one PDF per page ("PDF (individual pages)"), downloaded as a zip (or as a single file for one-page PDFs). Pages are extracted as-is, without re-rendering.
Export as a Zip
Doesn't convert anything — bundles every file currently shown in the gallery (after any filter) into a single zip, unchanged. Available by selecting "All" as the convert subject.
Image diff mode
Open a parent folder containing exactly two subfolders whose image files share the same filename (ignoring extension) to compare them. Opening a matched file in the lightbox shows both versions overlaid with a divider that follows your mouse — the alphabetically-first subfolder is on the left. Files without a match in the other subfolder, or matched pairs that aren't both images, display normally.
Alt text generation (AI)
Generates alt text for images with Chrome's built-in on-device AI (Gemini Nano) — nothing is sent to any server. Works with JPEG, PNG, WebP, GIF, SVG, and AVIF (formats usable in <img>), and the output language can be chosen with "Alt text language" in the Settings tab (when unset, it follows the browser language: Japanese or English). Select "All" as the convert subject and choose "Export alt text (AI)" to download a JSON file pairing each filename with its alt text, or use "Alt text" in the lightbox to generate and copy text for one image. Requires Chrome 148 or later, at least 22 GB of free disk space, more than 4 GB of VRAM, and 16 GB of RAM; the first run downloads the model. Animated GIFs are described from their first frame.
Bookmarks
Click the bookmark icon next to "Open Folder" to save frequently used folders and reopen them without browsing to them again. Adding one opens a native folder picker; reopening a bookmark only needs a quick permission confirmation instead of the full picker. Available in Chromium-based browsers only (Chrome, Edge, etc.), since it relies on the File System Access API.
Keyboard operation
Folder tree
Tab enters the tree on the selected folder. ↑ ↓ move between visible folders. → expands a closed folder; on the selected folder with nothing left to expand, it moves focus into the gallery. ← collapses an open folder. Enter / Space shows the folder's contents in the gallery; pressing it again moves focus into the gallery. Home / End jump to the first / last folder. Typing a character jumps to the next folder whose name starts with it.
Gallery
Tab moves between items. Enter / Space opens the item in the lightbox. ← returns focus to the selected folder in the tree.
Lightbox
← → navigate between files. Z toggles zoom mode (images and videos). C toggles the checker background (images and videos). 1 toggles actual-size display (images and videos). R rotates 90° counter-clockwise (images and videos). L toggles loop playback (videos). Esc releases or exits zoom, closes the lightbox, or stops the slideshow. Single-key shortcuts can be turned off in the Settings tab.