Please check the image file names you are using for your Gallery widget. Do they contain special characters in them such as ( ) or accents, etc..? If so, please try renaming your image file name so that it contains only plain English text with no characters. Here's how to rename your image file:
- Go to Files.
- Right-click on the file in the File Manager.
- Click Rename.
- Delete the file name but remember to leave the extension (e.g. .jpg).
- Enter a new file name before the extension.
- Click Rename File.
- You will need to re-add your images to your Gallery widget. Your thumbnails should now be displaying correctly.