Save the network map as a picture
Both live network maps got a small button in the top left corner today: Save image. It hands you a PNG of the map as you have it framed at that moment, and you can post it wherever you like.
The button sits on the aircraft map and on the ships map, and it saves whatever is on screen. Zoom into the Humber, pan to the Gulf, leave it on the whole planet, then press it. What you zoomed to is what lands in the file, at the full resolution your screen is drawing, so a retina laptop produces a picture that still looks sharp when someone opens it full size.
Why there is a strip under the map
The counts above the canvas, the UTC stamp and the legend in the corner are all ordinary page elements sitting around the map, not part of the picture the map draws. Export only the canvas and you get a field of coloured dots with no scale, no time and no source, which is a pretty image and a useless one.
So the saved file is the map plus a caption bar: the Skydex lockup, what the network is, the address of the page, the same numbers the page was showing, the date and time in UTC, and the legend when there is room for it. On a narrow phone export the legend is the first thing dropped, then the trailing counts, so the line never runs off the edge.
The date matters more than it looks. A snapshot of live traffic is only true for the minute it was taken, and a picture posted on Tuesday about Monday evening should say so on its face rather than in a caption somebody scrolls past.
What it does not do
It does not draw anything the map was not drawing. Private aircraft stay grey outlines with no identity, receivers still sit on their nearest city rather than their antenna, and no square of the coverage grid is traced back to a station. Saving a frame publishes exactly what the page publishes.
There is no server involved either. The file is composed in your browser from the canvas that is already on screen, so pressing the button costs the network nothing and works the same whether you are signed in or not.