{
  "schema": "https://storagestudio.us/schema/wiki-page.v1",
  "title": "Thumbnails, and why some accounts show plain icons",
  "slug": "thumbnails-in-finder",
  "url": "https://storagestudio.us/wiki/thumbnails-in-finder",
  "markdown_url": "https://storagestudio.us/wiki/thumbnails-in-finder.md",
  "category": "The Finder location",
  "category_url": "https://storagestudio.us/wiki/the-finder-location/",
  "tags": [
    "finder",
    "cloud accounts",
    "thumbnails"
  ],
  "summary": "The Storage Studio location shows picture, video and document thumbnails on accounts where reading a little of a file costs nothing. On storage that charges for each request it shows plain icons, so browsing never runs up a bill.",
  "published_at": "2026-10-01T06:19:52.000Z",
  "updated_at": "2026-10-01T05:37:33.000Z",
  "headings": [
    {
      "level": 2,
      "text": "Which accounts show thumbnails",
      "id": "which-accounts-show-thumbnails"
    },
    {
      "level": 2,
      "text": "What gets a thumbnail",
      "id": "what-gets-a-thumbnail"
    },
    {
      "level": 2,
      "text": "Gentle by design",
      "id": "gentle-by-design"
    },
    {
      "level": 2,
      "text": "Why not just show everything?",
      "id": "why-not-just-show-everything"
    }
  ],
  "links_out": [
    {
      "slug": "the-storage-studio-location-in-finder",
      "label": "Storage Studio location",
      "exists": true,
      "url": "https://storagestudio.us/wiki/the-storage-studio-location-in-finder"
    },
    {
      "slug": "large-folders-in-finder",
      "label": "Large folders appear a page at a time",
      "exists": true,
      "url": "https://storagestudio.us/wiki/large-folders-in-finder"
    },
    {
      "slug": "s3-compatible-storage",
      "label": "S3-compatible storage",
      "exists": true,
      "url": "https://storagestudio.us/wiki/s3-compatible-storage"
    },
    {
      "slug": "cloud-accounts",
      "label": "Cloud accounts",
      "exists": true,
      "url": "https://storagestudio.us/wiki/cloud-accounts"
    }
  ],
  "links_in": [
    {
      "slug": "large-folders-in-finder",
      "title": "Large folders appear a page at a time",
      "url": "https://storagestudio.us/wiki/large-folders-in-finder"
    },
    {
      "slug": "the-storage-studio-location-in-finder",
      "title": "The Storage Studio location in Finder",
      "url": "https://storagestudio.us/wiki/the-storage-studio-location-in-finder"
    }
  ],
  "diagrams": [
    {
      "kind": "flowchart",
      "caption": "How Storage Studio decides whether to draw a thumbnail",
      "outline": "- Finder is about to show a file\n  - leads to Is the account free to read from?\n- Is the account free to read from?\n  - No: leads to Plain icon\n  - Yes: leads to Picture, video or document?\n- Picture, video or document?\n  - No: leads to Plain icon\n  - Yes: leads to Read only the small part needed\n- Read only the small part needed\n  - leads to Could a preview be drawn?\n- Could a preview be drawn?\n  - Yes: leads to Thumbnail\n  - No: leads to Plain icon\n",
      "source": "%% caption: How Storage Studio decides whether to draw a thumbnail\nflowchart TD\n  A[Finder is about to show a file] --> B{Is the account free to read from?}\n  B -->|No| P[Plain icon]\n  B -->|Yes| C{Picture, video or document?}\n  C -->|No| P\n  C -->|Yes| D[Read only the small part needed]\n  D --> E{Could a preview be drawn?}\n  E -->|Yes| T[Thumbnail]\n  E -->|No| P"
    }
  ],
  "images": [],
  "screenshots_pending": [
    {
      "alt": "A Finder window in Demo Mode in icon view inside the Storage Studio location, showing a photos folder with picture thumbnails",
      "caption": "Thumbnails in a cloud account folder"
    }
  ],
  "faqs": [
    {
      "question": "Can I see all my cloud accounts in Finder on a Mac?",
      "answer": "Yes. Storage Studio adds a \"Storage Studio\" location to Finder's sidebar, with each connected cloud account and paired device as a folder inside, and a Finder button in the app's main window opens it. Files stay in the cloud until you open them. Folders you have visited open straight away and…",
      "url": "https://storagestudio.us/faq"
    },
    {
      "question": "Will opening cloud files in Finder fill up my Mac?",
      "answer": "No. Only files you actually open are downloaded, and you choose how long they stay on your Mac once you stop using them — from not at all up to a week, 24 hours by default (and longer when the drive keeps its copies on your external drive). After that they go back to being online-only and the…",
      "url": "https://storagestudio.us/faq"
    },
    {
      "question": "Is a locked Delta Drive folder the same as Finder's Locked checkbox?",
      "answer": "No. Finder's own Locked checkbox (in Get Info) only stops a file being changed or deleted by accident, and anyone using your Mac can untick it — it doesn't keep anyone out. A locked Delta Drive folder does: it opens only in Storage Studio on your Mac, with your 6-digit PIN and a one-time code we…",
      "url": "https://storagestudio.us/faq"
    }
  ],
  "text": "When you browse the Storage Studio location , Finder can show small previews of your photos, videos and documents, just like it does for files on your Mac. Storage Studio draws them by reading only a small part of each file, and only for the files Finder is about to show. On storage that charges you for every request, it shows plain icons instead, so browsing a folder never costs you money. Which accounts show thumbnails Thumbnails Plain icons Google Drive, Dropbox, OneDrive and Box S3-compatible storage iCloud Drive, and the Photos folder of an extra Apple ID Any storage that charges for each request SFTP and FTP servers, and paired devices Any account type Storage Studio doesn't recognise The Home folder on your external drive The rule is simple: thumbnails are drawn only where reading part of a file is free. Anything else gets plain icons, even if that means fewer pictures. Plain icons don't affect your files in any way; open a file and it downloads and opens as usual. What gets a thumbnail Photos and pictures , including common camera raw formats. Most cameras and phones store a small preview near the start of the file, and Storage Studio reads just that part. A small picture with no built-in preview is read whole. Videos from phones and cameras. Storage Studio reads only the start and the end of the file, which is enough for the first frame, instead of downloading the whole video. Documents , such as PDFs, Word, Excel and PowerPoint files, Pages, Numbers and Keynote files, text and web pages. Small ones are read whole; for a large PDF only the parts needed for the first page are read. If that isn't enough, the plain icon stays. How Storage Studio decides whether to draw a thumbnail Flowchart outline: How Storage Studio decides whether to draw a thumbnail Finder is about to show a file leads to Is the account free to read from? Is the account free to read from? No: leads to Plain icon Yes: leads to Picture, video or document? Picture, video or document? No: leads to Plain icon Yes: leads to Read only the small part needed Read only the small part needed leads to Could a preview be drawn? Could a preview be drawn? Yes: leads to Thumbnail No: leads to Plain icon Gentle by design Thumbnails are made only for files on screen. Scroll, and the next ones are fetched as they come into view. Only a few are fetched at a time, to stay light on your Mac and on the account. Any temporary file used to draw a thumbnail is deleted straight away. Drawing a thumbnail doesn't leave a downloaded copy of the file on your Mac. Why not just show everything? Some storage, including S3-compatible services, charges for every request, however small. Scrolling once through a folder of photos would mean a billed request for every icon. Storage Studio would rather show a plain icon than run up a bill you didn't ask for. See also: Large folders appear a page at a time · S3-compatible storage · Cloud accounts Common questions Can I see all my cloud accounts in Finder on a Mac? Yes. Storage Studio adds a \"Storage Studio\" location to Finder's sidebar, with each connected cloud account and paired device as a folder inside, and a Finder button in the app's main window opens it. Files stay in the cloud until you open them. Folders you have visited open straight away and… Will opening cloud files in Finder fill up my Mac? No. Only files you actually open are downloaded, and you choose how long they stay on your Mac once you stop using them — from not at all up to a week, 24 hours by default (and longer when the drive keeps its copies on your external drive). After that they go back to being online-only and the… Is a locked Delta Drive folder the same as Finder's Locked checkbox? No. Finder's own Locked checkbox (in Get Info) only stops a file being changed or deleted by accident, and anyone using your Mac can untick it — it doesn't keep anyone out. A locked Delta Drive folder does: it opens only in Storage Studio on your Mac, with your 6-digit PIN and a one-time code we…",
  "markdown": "When you browse the [Storage Studio location](https://storagestudio.us/wiki/the-storage-studio-location-in-finder), Finder can show small previews of your photos, videos and documents, just like it does for files on your Mac. Storage Studio draws them by reading only a small part of each file, and only for the files Finder is about to show. On storage that charges you for every request, it shows plain icons instead, so browsing a folder never costs you money.\n\n## Which accounts show thumbnails\n\n| Thumbnails | Plain icons |\n| --- | --- |\n| Google Drive, Dropbox, OneDrive and Box | S3-compatible storage |\n| iCloud Drive, and the Photos folder of an extra Apple ID | Any storage that charges for each request |\n| SFTP and FTP servers, and paired devices | Any account type Storage Studio doesn't recognise |\n| The **Home** folder on your external drive | |\n\nThe rule is simple: thumbnails are drawn only where reading part of a file is free. Anything else gets plain icons, even if that means fewer pictures. Plain icons don't affect your files in any way; open a file and it downloads and opens as usual.\n\n## What gets a thumbnail\n\n- **Photos and pictures**, including common camera raw formats. Most cameras and phones store a small preview near the start of the file, and Storage Studio reads just that part. A small picture with no built-in preview is read whole.\n- **Videos** from phones and cameras. Storage Studio reads only the start and the end of the file, which is enough for the first frame, instead of downloading the whole video.\n- **Documents**, such as PDFs, Word, Excel and PowerPoint files, Pages, Numbers and Keynote files, text and web pages. Small ones are read whole; for a large PDF only the parts needed for the first page are read. If that isn't enough, the plain icon stays.\n\n```mermaid\n%% caption: How Storage Studio decides whether to draw a thumbnail\nflowchart TD\n  A[Finder is about to show a file] --> B{Is the account free to read from?}\n  B -->|No| P[Plain icon]\n  B -->|Yes| C{Picture, video or document?}\n  C -->|No| P\n  C -->|Yes| D[Read only the small part needed]\n  D --> E{Could a preview be drawn?}\n  E -->|Yes| T[Thumbnail]\n  E -->|No| P\n```\n\n*Flowchart — How Storage Studio decides whether to draw a thumbnail. Outline:*\n\n- Finder is about to show a file\n  - leads to Is the account free to read from?\n- Is the account free to read from?\n  - No: leads to Plain icon\n  - Yes: leads to Picture, video or document?\n- Picture, video or document?\n  - No: leads to Plain icon\n  - Yes: leads to Read only the small part needed\n- Read only the small part needed\n  - leads to Could a preview be drawn?\n- Could a preview be drawn?\n  - Yes: leads to Thumbnail\n  - No: leads to Plain icon\n\n## Gentle by design\n\n- Thumbnails are made only for files on screen. Scroll, and the next ones are fetched as they come into view.\n- Only a few are fetched at a time, to stay light on your Mac and on the account.\n- Any temporary file used to draw a thumbnail is deleted straight away. Drawing a thumbnail doesn't leave a downloaded copy of the file on your Mac.\n\n## Why not just show everything?\n\nSome storage, including S3-compatible services, charges for every request, however small. Scrolling once through a folder of photos would mean a billed request for every icon. Storage Studio would rather show a plain icon than run up a bill you didn't ask for.\n\nSee also: [Large folders appear a page at a time](https://storagestudio.us/wiki/large-folders-in-finder) · [S3-compatible storage](https://storagestudio.us/wiki/s3-compatible-storage) · [Cloud accounts](https://storagestudio.us/wiki/cloud-accounts)\n\n- **Can I see all my cloud accounts in Finder on a Mac?** Yes. Storage Studio adds a \"Storage Studio\" location to Finder's sidebar, with each connected cloud account and paired device as a folder inside, and a Finder button in the app's main window opens it. Files stay in the cloud until you open them. Folders you have visited open straight away and… (https://storagestudio.us/faq)\n- **Will opening cloud files in Finder fill up my Mac?** No. Only files you actually open are downloaded, and you choose how long they stay on your Mac once you stop using them — from not at all up to a week, 24 hours by default (and longer when the drive keeps its copies on your external drive). After that they go back to being online-only and the… (https://storagestudio.us/faq)\n- **Is a locked Delta Drive folder the same as Finder's Locked checkbox?** No. Finder's own Locked checkbox (in Get Info) only stops a file being changed or deleted by accident, and anyone using your Mac can untick it — it doesn't keep anyone out. A locked Delta Drive folder does: it opens only in Storage Studio on your Mac, with your 6-digit PIN and a one-time code we… (https://storagestudio.us/faq)\n"
}