Add a screenshot panel to blueprints

[gth]

A screenshot helps visualise how a blueprint is meant to work - even more so given the various belt tricks that are possible.
A small screenshot covering the same area as the blueprint boundary could be part of the blueprint string and travel with it.

Mock-ups attached showing the 'create blueprint' option, and how it might look when 'using' a blueprint.

Not sure how much bigger it would make a blueprint string but then again I've seen some HUGE blueprints over the years. Also, text containing an image is pretty common (I'm looking at you, img src="data:image/png;base64, iVB...").

Thanks for reading this far.

[Muche]

Blueprint string of your setup is 725 characters/bytes long.
Screenshot of it is about 200 kb.

I believe the description field is meant to be used for such purposes.
People also use constant combinators/display panels to mark belt's expected items.