Hello,
Click on the 'View' button on the blue bar to toggle the icon view, or click on the arrow to the right of the View button then select either 'Small Icons', 'Large Icons' or 'Extra Large Icons' for a thumbnail view of your images.
If that doesn't work, ensure that the
'Always show icons, never thumbnails' option is disabled. Press the
Alt key on the keyboard and the menu options should appear below the address bar. Click
Tools > Folder Options > View tab > Ensure that the
'Always show icons, never thumbnails' is unchecked, apply then ok.