I use preloader in website: 
Required:
I tried to convert it to "svg" but with no good result. So I didn't change the file format.
CodePudding user response：
you don't have any Open Graph tags in your home page..so facebook took one screenshot of the page https://www.ionos.com/digitalguide/online-marketing/social-media/open-graph/
and another thing...your site have <html lang="en" but is not in english, this can confuse google.
The same problem in the news page, but fortunatly facebook is enought smart to take a picture from the html article tag, in case you have more than an image he can take one you wouldn't like, is always raccomended to use Open Graph data for socials sharing