Open a folder containing a photo saved on the PC, then choose View → Large icons in File Explorer. Try a JPEG that opens normally. If local photos still show generic icons, check the thumbnail setting in Folder Options before clearing the cache.
01Check where thumbnails are missing
Section linkCompare a known local JPEG in Pictures with a photo in the affected folder, using Large icons in both places. If the JPEG will not open, solve the file access or format issue first. If local photos show thumbnails but a network share does not, the problem is specific to that location. The small image on a file icon is separate from the large Preview pane.
02Turn thumbnails on in Folder Options
Section linkIn the File Explorer toolbar, open the three-dot menu and choose Options. In the Folder Options dialog, open the View tab. Clear Always show icons, never thumbnails, then choose Apply and OK. Go back to the folder and check the same JPEG again. If the setting was already cleared, leave it unchanged and continue to the cache check.
03Refresh only the thumbnail cache
Section linkIf several local photo folders are affected, search Start for Disk Cleanup and select the Windows drive if prompted. Leave only Thumbnails selected and clear every other checkbox. Confirm the cleanup, then reopen the folder and allow Windows time to regenerate the previews. The Thumbnails category clears cached images; it does not delete your original photos.
04Check with IT if the pattern points to a policy
Section linkOn a work or school PC, ask whether your organization uses a File Explorer policy to show icons only. Microsoft documents separate policies for files on the local computer and files in network folders. Tell IT whether the local JPEG opened, whether it showed a thumbnail, and which folder still showed only icons. That gives them a way to distinguish the policies from a file access issue.