How to handle the display of front-end images if the `thumb` or `logo` field returned by the document detail interface is empty?
When building a website with AnQiCMS, we often retrieve detailed document information from the backend interface.Among them, images are an indispensable part of content display, and the `thumb` (thumbnail) and `logo` (logo) fields are particularly important, as they are usually used in article lists, the top or sidebar of detail pages, and other locations.However, in actual development, we may encounter situations where these fields return empty.How should we handle it elegantly when the front-end gets an empty value, to ensure the friendliness of the user interface (UI) and the integrity of the content