A couple weeks ago I published a mini-review of the new Gutenberg editor in WordPress. I said there that there was no clean way to embed images from Flickr.
I was wrong. It’s stupefyingly easy. You just paste the Flickr embed code directly into an empty block. The image appears instantly! It also hyperlinks back to the Flickr page from which it came, per Flickr’s terms of service.

This is far easier than how we all had to embed Flickr images in any previous WordPress editor. Given that I use Flickr to host my photographs, Gutenberg is making creating posts significantly faster for me!