DOC: Add link gen. screenshot, update example gif

[consideRatio]

This is an update of the documentation example gif animation, and an extension where also a screenshot of the link generator is included.

This PR was motivated by me making a digital poster for a conference and wanted a shorter and smaller in size gif animation, that preferably also demonstrated the opening of a specified notebook, preferably in jupyterlab. Having made it, do we want to use it here?

---

Example use

1. The nbgitpuller link generator is used to create a link.

   

2. The link is clicked.

   

[choldgraf]

This looks great - two quick suggestions for extra words to clarify what's going on.

Any strong reason not to just re-use the raw.githubusercontent.com GIFs instead of embedding them in this repository? It seems many others are doing this too.

[consideRatio]

Any strong reason not to just re-use the raw.githubusercontent.com GIFs instead of embedding them in this repository? It seems many others are doing this too.

I don't understand this question clearly @choldgraf. I have some thoughts that could be relevant to it though.

• I want a README.md file to render well at pypi.org as well as github.com
• I could make the docs point to an external URL, but if the .gif is part of the repo anyhow, I figure its fine to reference it directly instead

[choldgraf]

I just mean link the images directly from their raw.github.com URL, rather than committing them to git history. Basically use GitHub as a CDN so that we don't grow our git repo size with images. I'm not sure whether that has implications for working on PyPI though

[consideRatio]

Okay hmm, but they raw url refers to the github repo, but it github can indeed be used as a cdn.

To not grow the github repo size, we can post the image into a github issue and then reference it, but its more complexity to maintain and understand in a way.

I figure this is what i like doing for this repo and situation given that we don't change this regularly and wont grow beyond for example 10 MB anytime soon.

[choldgraf]

Sounds good - I don't mean my comment to block this PR if others prefer to just commit things to the repository. I'll merge this in! Thanks @consideRatio for improving these docs :-)