Cannot preview pictures in Windows. File Explorer thumbnails not showing

Show thumbnails in Explorer and set default apps to open images

File Explorer in Windows should show thumbnails of images like photos on the disk, which makes finding them easy. Except when it does not show thumbnails or previews. Fix image preview issues.

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There are several issues here and one is that thumbnails of photos are not displayed when browsing the disk in File Explorer, which used to be called Windows Explorer. You might just see a generic file icon for every image instead of a thumbnail – a small postage stamp sized image.

It makes it impossible to see what an image file or photo is without opening in it a photo editing program, which is tediously slow to do when there are many files.

Another problem you may have is that double clicking photo files in an Explorer window does not show the photo or that it appears in the wrong application instead of the one you want to use to view it or edit it.

If you use an Apple Mac, you may be used to selecting an image file and pressing the spacebar to preview it. That does not work on Windows PCs, which can be frustrating. Is there no way to preview files? Let’s take a look at these issues.

Show thumbnails in File Explorer

  1. Open File Explorer in Windows
  2. Go to a folder that contains images, such as the Pictures folder
  3. Click View in the menu bar if the toolbar ribbon is not visible
  4. Select Large icons
Windows File Explorer view options

Image files should now show thumbnails, small versions of the full-size image, in File Explorer. Other files also show thumbnails, like PDF and Word documents.

Set folder options

If thumbnails are not visible, click View in File Explorer to show the toolbar ribbon and then click Options on the right. Select the View tab in the window and clear the checkbox next to these settings:

  • Always show icons, never thumbnails
  • Display file icon on thumbnails

Click the Apply to Folders button at the top and then click OK. It may help to click the Reset Folders and Restore defaults buttons in this window.

Folder options in Windows File Explorer

If there is no immediate change, refresh the window contents. Right click an empty part of the Explorer window and select Refresh from the menu.

Online images

Thumbnails may not appear in Explorer if files are stored online and there is no internet connection or online storage is disabled. OneDrive for example, syncs files between the OneDrive folder on the PC’s disk with your OneDrive online storage. Make sure that OneDrive is running and syncing and everything is up to date or you may have issues seeing thumbnails or previewing images in OneDrive folders/

Click the OneDrive icon in the taskbar, it may be hidden in that popup panel. Then click Help & Settings. Make sure syncing is not paused.

Clear the thumbnail cache

It takes time and processing power to generate thumbnails from large images, so once they have been created, Windows saves them in a cache. When images are displayed in an Explorer window, the thumbnails can be fetched from the cache faster than generating them from the original files. It is possible that the thumbnail cache is corrupted if some or all thumbnails are not displaying and if this happens, it is best to delete the cache. It will be recreated automatically with fresh thumbnails.

Disk Clean-up options in Windows

Click the Start button and type ‘disk clean‘. Disk Clean-up is suggested and clicking Open runs this system utility. Select the Windows startup disk c: as suggested. Among the list of items that can be cleaned is Thumbnails. Make sure the checkbox is ticked and click OK. It cleans other items, like Temporary files and Recycle Bin, which can be useful, too.

Show the Preview pane

If you want to preview files and see what they are before you open them, show the Preview pane in Explorer. It is a great way to browse the files in a folder, especially when they are images.

  1. Make the Explorer window large. Extra space is needed for the Preview pane
  2. Click View in the menu bar if the ribbon toolbar is not visible
  3. Click the Preview pane icon at the left side of the toolbar
Windows File Explorer preview pane

Now when a file is selected, a large preview is shown on the right. Resize the window to make it bigger or smaller. Let the mouse hover over the divider between the three sections and click and drag the border to resize each part. It is useful to set the view to List and use the keyboard to move up and down through the files and view the previews.

Customize folders for pictures

Folders can be optimized for certain types of file and this helps File Explorer show the right information when a folder is opened. There can be documents folders, pictures folders, music folders and videos folders and the contents are all very different. For example, music files are different to Word and Excel documents and knowing what files to expect helps Explorer. Setting the Pictures type for a folder can help when thumbnails of photos do not show.

Customize folders in Windows File Explorer

Right click a folder in File Explorer or right click the Pictures folder in Explorer’s sidebar. Select the Customize tab in the window that opens and at the top, under Optimize this folder for, select the appropriate type, such as Pictures for folders containing photos and other images.

Check performance settings

You might expect there to be a simple, single on/off switch to show or not show thumbnails on image icons, but there isn’t and here is yet another place where there are thumbnail settings.

  1. Click the Start button and type ‘system settings
  2. Click View advanced system settings in the search results
  3. Click the Settings button in the Performance section
  4. Make sure that Show thumbnails instead of icons is set
Windows system settings that affect performance and appearance

There is also an option to Save taskbar thumbnail previews, which doesn’t need to be set, but you could try it anyway.

Add HEIF extensions

There are many image file formats and .jpg files are the most common because they require little storage space. A lot of photos will fit on the disk or in a camera or phone’s storage when in .jpg format. Windows knows how to show file icon thumbnails and show full size .jpg images.

HEIF (High Efficiency Image File) is a new file format that is even better than .jpg and some cameras and phones store photos as .heic or .heif files. The iPhone uses .heic file format for photos. Windows cannot show thumbnails or images.

However, support for HEIF images can be added. A Windows update may come along that includes it, but for now it must be added. Open the Windows Store app and search for HEIF. Download and install HEIF Image Extensions.

A lot of comments on the page say it does not work and it has a low score on the store. I can only say that it works perfectly for me and I can view thumbnails in Explorer and open photos taken with my iPhone and stored in .heic format.

Set the default app for photos

If thumbnails are not showing or if clicking an image file like a photo does not open or opens int he wrong app, it could be because there is no default app or the wrong app is associated with that type of file. Setting the default app to the one you want to use can cure these problems. Here’s how to do it.

  1. Right click a file in Explorer, such as a .jpg photo
  2. Move the mouse over Open with on the menu that appears
  3. Click Choose another app on the flyout menu
  4. Select the app you want to use from the list of installed apps
  5. Tick the checkbox Always use this app to open .jpg files
  6. Click OK
The Open with menu in Windows File Explorer

This should be repeated with every file type you want to open, like .png files, .tif files, .gif files and so on.

Set the default app to open a file in Windows

It works with other files like text files, documents, spreadsheets and so on.

Add QuickLook

QuickLook is a great feature on the Apple Mac and it enables you to preview many types of files, including photos, PDFs and documents. Just select a file in Finder and press the spacebar to preview it in a popup window.

If only Windows had this. It does! Well, once you have added the free QuickLook app. Search for it in the Microsoft Store and install it. To preview a file, just select it in Explorer and press the spacebar. It is simple, but very useful.

Add One Commander

If thumbnails are not showing in File Explorer, try a replacement like OneCommander. This free app can be found in the Microsoft Store, but I prefer the portable app downloaded from the One Commander website. Just unzip it, open the folder and click OneCommander.exe to run it. Pin the icon to the taskbar to make it easy to run next time.

One Commander is an alternative to Windows File Explorer

Click the toolbar button to select the file view and there are two thumbnails options, Thumbnail Grid and Thumbs+Details. The second option shows photo details like ISO setting, shutter speed and focal length of photos, which is interesting and useful if you are a photographer.

One Command has many great features and it is worth getting to know. There are other File Explorer alternatives that also offer thumbnail views.

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About Roland Waddilove 396 Articles
Roland Waddilove is interested in technology: Computers, phones, gadgets, software and internet. Long ago he worked on computer magazines, but is now mostly a tech writer for the web.