That's an interesting and very nice idea Lucas. Thanks for suggesting that. We've added it to our Feature Requests list.
Today it is quite common to share absolved routes/tracks via smartphone. You are addressing this with the option t download a route as an image (PNG/GIF/JPG) and the option to set the dimensions to fit Facebook or Twitter needs.
I think this feature could be enhanced a lot with perhaps not much of work as Plotaroute already has a great infrastructure of tools (thinking of the options available when printing routes).
Perhaps it would be possible to add options to enhance that "share images" by adding title, total ascent, distance in an attractive way. Even the elevation profile would be nice.
Some people would perhaps also like to use a photo as background image instead of a map - but that's would be more work I guess and it would perhaps not fit as good into Plotaroute's purposes...
There are some tools for doing things like that and I guess that many users would like to use Plotaroute for this as not everybody wants to use Strava or Google and install even more apps for those little things all the time.
Perhaps you can have a look here to understand what I'm talking about (again: the normal Map as background is of course the main goal): https://marcbaldwin.github.io/velographic/