Image sitemaps increase your site's chances of being found in Google Image Search, and you don't have to have a dedicated images sitemap; you can also use the images extension in your regular sitemap.
Google says that "Google may use the text on the page instead of the text you provide in your sitemap if the text of the page is deemed more useful than the information in the sitemap." They are talking about the text delivered via the description. In addition to the description, you can also provide Google with a thumbnail, video length, rating, family-friendliness, and more full list of video XML sitemap metadata . For sites that make heavy use of video, this certainly makes sense. For everyone else, it's relatively optional.
News sitemaps are different in that you should always have namibia mobile database a separate News XML sitemap. Google does not recommend or provide an extension in this case. News sitemaps help Google discover and rank new articles, which is particularly challenging in the publishing industry because of the large volume of content it produces. Although Google states that it does not like publishers who have News sitemaps, it does help get top stories ranked in Google News faster.
News Sitemaps have special requirements:
Include articles no older than 2 days.
Do not add more than 1000 new entries to an existing sitemap at one time.
Update existing sitemap for article updates.
You can also use XML sitemaps to define and instruct Google on certain meta tags. One example is hreflang; you can add that as an extension to your sitemap.