You are posting links to search engine results.
If your link has "google.com", "bing.com", "duckduckgo.com", etc. in them they will be deleted.
If you want to post an image, it needs to be hosted somewhere (search engines do not allow them linked directly) and then use the Insert Image icon in the menu bar to paste the hosted image URL.
You can attempt to go to the site where the image is hosted (not the search engine page, but where it takes you when you click the images) and attempt to right-click and copy image URL and paste that into the Insert Image box, but a lot of sites block off-site linking so it may or may not work.
Because browsers cache images once viewed, it will appear to work for YOU only if you already viewed the image, but it may appear as a broken image to everyone else.
Otherwise, you will need to download the image and then upload it to an image hosting service to post it with with the Insert Image feature.