When you create a theme, a preview image will be created for your theme, which will appear in your Themes Dashboard:
If you'd like to update the image that appears, you can do so from your theme! To do so:
- Open your Theme.
- Click into Theme Tab in the top right-hand corner.
- Click the gear icon next to "Theme."
- Click on the current preview image.
- Upload your new preview image.
- Click "Update Theme."
Now, you're all set! This will be the new preview image for your theme.