If you want to display an image on a webpage, you have a couple of choices. You can host the image on your webserver, or you can embed the image / in-line link the image on a third-party server. In both cases, the image appears as a part of the webpage.
In the Court of Appeals for the Ninth Circuit, embedding an image and in-line linking an image is lawful. Perfect 10, Inc. v. Amazon.com, Inc., 508 F.3d 1146 (9th Cir. 2007); Perfect 10 v. Google, Inc., 416 F.Supp. 828, 844 (C.D. Cal. 2006). Many courts have followed the Ninth Circuit's reasoning, and this has allowed the Internet to become as rich with content.
However, a United States District Court for the Southern District of New York just found that in-line linking constitutes direct copyright infringement because it violates the copyright holder's exclusive right to publicly display a work. Goldman v. Breitbart News Network, LLC, et al., 1:17-cv-03144-KBF (S.D.N.Y. Feb. 15, 2018) at 16-17 (a copy of the order can be found here on Mega.nz). If this court's reasoning takes off, then people won't link to content which will make the Internet less rich with unlawful content, but probably will encourage the creation of more lawful content.
I assume that this Order will be appealed to the Court of Appeals for the Second Circuit. If the Second Circuit does not reverse, then there will be circuit split and hopefully the U.S. Supreme Court will step in and hear this case.