Technically, Medium's policy is that all images must be properly sourced for copyright reasons.

You can use Flickr, as long as you use an image that has a creative commons license.

The use of copyrighted images in social media memes and such is too out of control to govern, but Medium authors who use copyrighted images without attribution are breaking Medium's terms of use, and are lazy.

Screenshots count as fair use, as do some other things.

Anyway, point is, it's a different situation. Adobe is borrowing the use of other people's work without their permission.