'text' : 'ui_browse_properties_scheme_color', 'description' : 'Exemplary wallpaper to demonstrate new ember particle preset.', Open the project.json file with a text editor, it will look something like this: Create a new wallpaper as usual and open its project directory with Edit -> Open in Explorer. If you deleted your project you can still overwrite it, but depending on the type of wallpaper you published, you may not be able to edit it anymore. Go to Steam -> Publish and the button will say Publish Update, therefore no new wallpaper will be created and instead your old one will be updated.
To update a wallpaper, simply open your project in the editor again.