In certain cases, File explorer may end up showing app icons instead of thumbnails for images and videos. However, fixing this issue is not as complicated as it might seem. And here are all the steps that you have to follow: From File Explorer, click on the triple dotted icon on the menu bar. Select options. Then from the Folder Options Window, click on the view tab. Under the advanced settings, uncheck the checkbox for the Always show icons, never thumbnails option. Finally, click on Apply, then OK to save the changes.