To keep page thumbnails beside a PDF as you read on a Mac, open the document in Preview and choose View > Thumbnails. The sidebar stays available in that document window while you scroll through pages, and clicking a thumbnail jumps to that page. If you hid the sidebar, choose View > Thumbnails again to bring it back. View PDFs and images in Preview on Mac

Show the thumbnails beside your PDF

Open the PDF in Preview, either with File > Open or by double-clicking it in Finder. In the menu bar at the top of the screen, choose View > Thumbnails. Preview displays small page previews in the sidebar alongside the document. This is the standard thumbnail view for navigating a multipage PDF. Get started with Preview on Mac

If the sidebar is already open but shows a table of contents or another panel, choose View > Thumbnails to switch its contents. A table of contents appears only when the PDF has one; it is different from the thumbnail list. If the sidebar is hidden, the same Thumbnails command opens it. Apple also lists View > Contact Sheet as a way to show thumbnails, but Contact Sheet presents pages as a sheet of small previews, so Thumbnails is the straightforward choice when you want to read a page and keep navigation at its side. View PDFs and images in Preview on Mac

Make the sidebar practical for reading

The sidebar takes space from the document area. To adjust the balance, move the pointer to the divider between the sidebar and the page, then drag it left or right. Widen it if you need to distinguish pages from their previews; narrow it if you want more room for the PDF text. Apple documents resizing the sidebar this way, but it does not provide a numeric width setting in this viewing workflow. View PDFs and images in Preview on Mac

Choose a page layout that suits the material. View > Continuous Scroll lets you move through pages in a continuous document, while View > Single Page shows one page at a time and View > Two Pages places two pages side by side. These change how pages appear in the main reading area; they are separate from the choice to show thumbnails in the sidebar. For ordinary reading with frequent page jumps, start with thumbnails and continuous scroll, then change the page layout if the PDF’s design calls for it. View PDFs and images in Preview on Mac

Navigate without losing your place

Click a thumbnail to jump directly to that page. To move through pages using the keyboard, Apple documents the Up and Down Arrow keys for navigating a multipage PDF; its Preview shortcut guide also lists Option–Down Arrow for the next page and Option–Up Arrow for the previous page. Shortcuts can vary with keyboard layout and language, so check Preview’s menu bar if a documented shortcut behaves differently on your Mac. Get started with Preview on Mac, Keyboard shortcuts in Preview on Mac

You can also choose Go > Go to Page when you know the page number. That is useful for a specific destination, while thumbnails are better when you want to scan nearby pages or choose one by its visual content. Trackpad users can swipe up or down with two fingers to scroll. View PDFs and images in Preview on Mac

If the thumbnails disappear

If you can no longer see the page previews, first check the View menu. Choose Thumbnails to restore that sidebar mode; choose Hide Sidebar only when you intentionally want more room for the page. If the sidebar is visible but shows a different panel, switch back to Thumbnails. The active menu item and available commands can depend on the current view, so use the menu labels shown by Preview rather than relying on an assumed keyboard shortcut.

Apple’s current Preview guide explains how to show, resize and use thumbnails in an open PDF. It does not establish that a particular sidebar choice will remain in effect for every PDF you open in the future. If a later document opens without thumbnails, apply View > Thumbnails in that document window. This keeps the steps grounded in controls Apple documents instead of relying on older preference instructions or hidden settings.

Keep the reading task easy to resume

For a simple routine, open the PDF, show thumbnails, set a comfortable sidebar width, and select the page layout you want. Use the thumbnail list for visual jumps and scroll or page keys for sequential reading. If you are also keeping related Mac windows and to-dos together by goal, Wallo can help organize those existing open windows and tasks locally with keyboard focusing; it does not change Preview’s sidebar or make thumbnails persist across documents.

The key control is View > Thumbnails. Once the sidebar is open, resizing it and choosing a suitable page layout let you keep page navigation close without interrupting the reading flow. If it vanishes in another document, use the same menu command there.

Sources